H- 
 
 HAWAII AGRICULTURAL EXPERIMENT STATION 
 HONOLULU, HAWAII 
 
 Under the joint supervision of the 
 
 UNITED STATES DEPARTMENT OF AGRICULTURE 
 
 AND THE UNIVERSITY OF HAWAII 
 
 BULLETIN No. 74 
 
 THE EDIBLE PASSION FRUIT 
 IN HAWAII 
 
 By 
 W. T. POPE, Senior Horticulturist 
 
 Issued September 1935 
 
 \% NOV J*«.*»5 
 
 UNITED STATES DEPARTMENT OF AGRICULTURE 
 
 OFFICE OF EXPERIMENT STATIONS 
 
 For sale by the Superintendent of Documents, Washington, D. 
 
 *£, Price 5 cents 
 
 Va 
 
HAWAII AGRICULTURAL EXPERIMENT STATION, HONOLULU 
 
 [Under the joint supervision of the Office of Experiment Stations, U. S. Department of 
 Agriculture, and the University of Hawaii] 
 
 James T. Jaedinb, Chief, Office of Experiment Stations. 
 D. L. Crawford, President, University of Hawaii. 
 
 STATION STAFF 
 
 O. C. Magistad, Director. 1 
 
 J. M. Westgate, Consultant in Tropical Agriculture.* 
 
 C. P. Welsie, Agronomist. 
 
 L. A. Henke, Animal Husban&num. 
 
 J. C. Ripperton, Chemist. 
 
 Earl M. Bilger, Collaborator in Chemistry. 
 
 Mrs. Leonora Neuffer Bilger, Collaborator in Chemical Research. 
 
 W. T. Pope, Senior Horticulturist. 
 
 Carey D. Miller, Specialist in Nutrition. 
 
 C. M. Bioe, Poultry Husbandman. 
 
 H. A. Wadsworth, Irrigation Engineer and Soil Physicist. 
 
 C. J. Hamre, Histologist. 
 
 D. W. Edwards, Junior Chemist. 
 
 Ruth C. Bobbins, Assistant, Nutrition Investigations. 
 
 John Castro, Plant Propagator. 
 
 M. Takahashi, Assistant in Agronomy. 
 
 Philip Young, Assistant in Agronomy. 
 
 G. W. H. Goo, Assistant in Animal Husbandry. 
 
 E. T. Fukunaga, Assistant in Chemistry. 
 Stephen Au, Laboratory Assi»t<mt in Chemistry. 
 W. B. Storey, Graduate Assistant in Horticulture. 
 
 HALEAKALA SUBSTATION 
 
 H. F. Willey, Superintendent, Mahawao, Island of Maui. 
 
 KONA SUBSTATION 
 
 R. K. Pahau, Superintendent, Kealakekua, Island of Hawaii. 
 
 1 Appointment effective July 1, 1935. 
 
 2 Director to June 30, 1935. 
 
HAWAII AGRICULTURAL EXPERIMENT STATION 
 HONOLULU, HAWAII 
 
 Under the joint supervision of the 
 
 UNITED STATES DEPARTMENT OF AGRICULTURE 
 
 and the 
 
 UNIVERSITY OF HAWAII 
 
 BULLETIN No. 74 
 
 Washington, D. C. 
 
 September 1935 
 
 THE EDIBLE PASSION FRUIT IN HAWAII 
 
 By W. T. Pope, Senior Horticulturist 
 
 CONTENTS 
 
 Introduction 
 
 Botanical relations 
 
 Pollination habits and unfruitfulness 
 
 Composition of fresh passion fruit (Passiflora 
 
 edulis) 
 
 Passion fruit juice 
 
 General cultural requirements 
 
 Selection of sites and soils 
 
 Propagation 
 
 Soil preparation 
 
 Trellises and planting 
 
 Tillage 
 
 Fertilizers.. 
 
 Page i 
 1 
 
 General cultural requirements— Continued. 
 Pruning 
 
 Insect enemies and plant diseases 
 
 Harvesting and marketing 
 
 Page 
 
 Descriptions of edible passion fruits 11 
 
 Purple passion fruit 11 
 
 Yellow passion fruit . 13 
 
 Sweet granadilla or waterlemon 13 
 
 Giant granadilla 16 
 
 Bell-apple 18 
 
 Sweet calabash 20 
 
 Literature cited — - 22 
 
 INTRODUCTION 
 
 Possibly half a dozen species of edible passion fruit have been in 
 cultivation in Hawaii for the last half century. Several of these 
 species have been disseminated in certain localities and are now 
 growing as a part of the natural vegetation. Only comparatively 
 recently has effort been made to grow the fruit commercially in 
 Hawaii. Investigation has shown that it is of relatively easy culture 
 and is well adapted to Hawaiian conditions. The most useful species 
 grow best in the cooler, moist parts of the Tropics, although they are 
 not considered exacting in their climatic and soil requirements. 
 
 The relatively small amount of space required by the passion fruit 
 plants and their habit of fruiting early adapt them to temporary 
 intercropping with such permanent orchard trees as require 6 or 8 
 years to come into regular bearing and need their properly allotted 
 space. 
 
 The passion fruit may be used in many ways for food and bever- 
 age purposes and it may find a market both in Hawaii and on the 
 mainland of the United States. 
 
 No insect pests or plant diseases have yet been reported as seriously 
 attacking passion fruit plants in Hawaii. 
 
 144158°— 35 1 1 
 
2 BULLETIN 7 4, HAWAII EXPERIMENT STATION 
 
 The Hawaii Agricultural Experiment Station has been conducting 
 experiments with the edible passion fruit since 1924. The first of 
 these was started at the central station in Honolulu, but field experi- 
 ments have also been carried on at the Kona substation, Island of 
 Hawaii, since 1931. In addition, many small field tests have been 
 made in cooperation with growers in various parts of the Territory. 
 
 Botanical classification, habits of .pollination, propagation, and 
 general cultural requirements have also been studied by the station 
 (12, p. 23; 17)} 
 
 BOTANICAL RELATIONS 
 
 All passion fruit species belong to the genus Passiflora. They are 
 woody, perennial climbers indigenous in tropical America. Most 
 Passifloras are ornamentals, but a few are cultivated for their edible 
 fruit. The edible fruit is similar in form to that of certain kinds 
 of melons and of the papaya. Striking examples are the giant 
 granadilla, muskmelon, and the common round-fruited papaya. 
 Early botanists recognized them as of the same great family. Pos- 
 sibly for other reasons, however, they are now classified in separate 
 families — Passifloraceae, Cucurbitaceae. and Papayaceae, respec- 
 tively. Practically all species of the genus Passiflora are character- 
 ized by either entire or lobed leaves arranged alternately at nodes 
 along the stem and branches and have simple tendrils from nodes 
 to hold the growing plants in place. The flowers are conspicuous 
 because of unusual form and varying combinations of beautiful 
 colors. The different kinds of edible passion fruit are not only at- 
 tractive in form and color but are generally pleasing in flavor. The 
 species having edible fruit, now growing in Hawaii, are as follows: 
 Purple passion fruit (Passiflora edulis}, yellow passion fruit (P. 
 edulis forma flavicarpa), 2 sweet granadilla or waterlemon (P. ligu- 
 laris), giant granadilla (P. quadrangularis) , bell-apple (P. lauri- 
 folia), West Indian sweet calabash (P. rrwliformis), red-fruited 
 passion vine (P. foetida), green-fruited passion vine (P. ciliata), 
 white-flowered passion vine (P. alba), and inkberry (P. suberosa). 
 The last four mentioned have little, if any, value for human con- 
 sumption but are eaten and disseminated by birds. The maypop 
 (P. incarnata) is mentioned as of early introduction to Hawaii by 
 Hillebrand (8, p. 139), but no recent reports have been noted. 
 
 POLLINATION HABITS AND UNFRUITFULNESS 
 
 Several species of Passiflora are irregular in their habits of setting 
 fruit in Hawaii. This is attributed to unsatisfactory pollination. 
 These species are evidently not in an environment similar to that in 
 which they developed in their native land. 
 
 The flowers are unusual in form, attractive in colors and odor, and 
 contain an abundance of nectar indicating that they depend con- 
 siderably upon live agencies to assist in pollination. The nectar is 
 so located that only certain kinds of pollen carriers, such as carpenter 
 bees (Xylocopa varipuncta), a species of bumblebee; large moths; 
 
 1 Italic numbers in parentheses refer to Literature Cited, p. 22. 
 
 2 The yellow passion fruit was identified by E. P. Killip from specimens and photo- 
 graphs sent him bv the Hawaii Experiment Station as a yellow-fi'uited form of Passi- 
 flora edulis. Later it was described as Passiflora edulis forma flavicarpa by Degener 
 
THE EDIBLE PASSION FRUIT IN HAWAII 6 
 
 and several kinds of humming birds, are able to get it. These pollen 
 carriers are of such size that the parts of their bodies to which pollen 
 adheres will come in contact with both stamens and the stigmatic 
 parts of the pistil. These pollen carriers, in their eager quest for 
 nectar, visit many flowers frequently, and hence naturally have 
 ample opportunity to carry pollen to many receptive stigmas. In 
 Hawaii, carpenter bees are frequently seen visiting passionflowers, 
 moths are rarely seen, and humming birds apparently do not exist. 
 
 It is believed that dry sunny conditions, w T ith breezy trade winds, 
 also aid in transmitting pollen from one flower to another and from 
 stamens to pistils of the same flowers. There are, however, failures 
 in pollination when both carpenter bees and breezes are present. 
 Even hand-pollination has failed. These failures have been reported 
 from many countries where Passifloras are grown. Investigation has 
 shown that some species often have protandrous flowers, that is, the 
 pollen of the anthers is ripe before the stigmas are ready to receive 
 it. The protandrous habit, no doubt, is a natural condition' of a 
 number of Passifloras and of some other kinds of plants. It is be- 
 lieved to have proven a means of bringing about cross-pollination of 
 species and possibly of varieties. The habit, in the case of the Passi- 
 flora, is closely associated with unusual form of floral parts, par- 
 ticularly of the essential organs (stamens and pistils). 
 
 The yellow passion fruit (P. edvMs fldvicarpa) is the most im- 
 portant and the most variable of the passion fruits in its pollination 
 habits. Faulty pollination is undoubtedly a frequent cause of scant 
 fruit production. 
 
 The bell-apple (P. lawvfolia) is a prolific bloomer but invariably 
 fails to produce fruit in proportion to the number of flowers. 
 
 The large purple strain of P. edulis, grown at the Hawaii Experi- 
 ment Station, is a scant bearer, and some of the fruits are also defec- 
 tive in having a portion of the interior without seeds and edible pulp, 
 possibly due to faulty pollination. The size of fruit and defective 
 pollination habits are apparently transmitted in this seedling strain. 
 
 The unfruitfulness of certain Passiflora species is not peculiar 
 to the Hawaiian Islands. Macmillan (.9, p. 267) states that P. lauri- 
 fol'm has been in cultivation in Ceylon and parts of Asia proper 
 for many years without fruiting. Popenoe (18, p. 24.2) notes that 
 P. edulis, in some countries, fails to produce fruit. It has been 
 stated (14) that the large purple variety or strain of P. edulis 
 is a shy bearer. 
 
 The giant granadilla (P. quad ran gularh) . when grown in South 
 Queensland, Australia, is reported by Barnes (J, p. 675) as often be- 
 ing a shy bearer, and this he attributes to the flowers being protan- 
 drous. He suggests that in the absence of insects to transmit the 
 pollen from young blossoms to fertilize the older flowers, hand- 
 pollination be practiced. Protandrous conditions of the giant gran- 
 adilla have not been reported in Hawaii. However, cultivation of 
 this species is rare and but little study of it has been made. 
 
 Both the yellow passion fruit and the bell-apple grow mostly 
 at altitudes below 500 feet in Hawaii. A few trials have been made 
 at the Kona substation, altitude 1,500 feet, and in cooperation with 
 growers on the Island of Hawaii, at 1,000, 1,200, and 1,500 feet, but 
 a fair set of fruit is rarely produced. Heavy yields have been pro- 
 
4 BULLETIN 74, HAWAII EXPERIMENT STATION 
 
 duced near sea level on both the windward and the leeward side of 
 Oahu. Plantings farther inland at 100 to 1,200 feet elevation make 
 vigorous growth but rarely produce any comparatively large crops 
 of fruit. A small planting made at the central station in Honolulu 
 in 1924, at about 60 feet elevation, gave a heavy crop in the summer 
 of 1927. The plants blossomed abundantly once or twice in succeed- 
 ing years, but set very few fruits, even though carpenter bees were 
 observed visiting the flowers, which, in this variety, are open in 
 the afternoon only. Hand-pollination has given no better results. 
 These unsatisfactory pollination habits are no doubt due in part to 
 protandrous characters peculiar to certain species of Passiflora. 
 
 Good yields of this variety have been obtained by the station and 
 cooperative growers, mainly in hot, dry localities where the pollen 
 may have a chance to become relatively dry, so that it may be easily 
 transmitted by both the breezes and the carpenter bees, and where 
 the warm, dry air encourages early maturity of the stigmas of the 
 pistil before the closing of the flowers at nightfall. For good growth 
 and vigor under these conditions, irrigation would usually be re- 
 quired. Special attention must also, be given to the arrangement of 
 the rows in the field and to providing a type of trellis which will give 
 the plants a chance to expose all of the flowers to strong sunlight 
 and free circulation of the air. The warm, dry atmosphere tends 
 to ripen the stigmas before it is too late in the afternoon for cross- 
 pollination by natural agencies. 
 
 COMPOSITION OF FRESH PASSION FRUIT (PASSIFLORA EDULIS) 
 
 Kesults of analyses of fresh passion fruit are given in the follow- 
 ing tabulation : 
 
 Fresh passion fruit: Percent 
 
 Rind 51.00 
 
 Pulp (including seeds and 
 
 juice) 3 49.00 
 
 Seeds 20.20 
 
 Juice 28.80 
 
 Rind on moisture-free basis: 
 
 Protein (NX 6.25) 9. 53 
 
 Crude fat (ether extract) _ _ .60 
 
 Nitrogen-free extract 52. 84 
 
 Crude fiber 30.10 
 
 Total ash 6. 93 
 
 Calcium (Ca) .46 
 
 Phosphoric acid (P) . 18 
 
 Seeds on moisture-free basis: 
 
 Protein (NX 6.25) 12.70 
 
 Crude fat (ether extract) _ _ 8. 32 
 
 Nitrogen-free extract 18.36 
 
 Crude fiber 59.20 
 
 Total ash 1.92 
 
 Seeds on moisture-free basis — 
 
 Continued. Percent 
 
 Calcium (Ca) .03 
 
 Phosphoric acid (P) .66 
 
 Juice as prepared from fresh 
 fruit: 
 
 Water 79.80 
 
 Protein (NX 6.25) .60 
 
 Fat 
 
 Crude fiber 
 
 Ash . 
 
 Carbohydrates (by differ- 
 ence) 19, 
 
 Acidity (calculated as cit- 
 ric acid) _ 2. 
 
 Calcium (Ca) 
 
 Phosphoric acid (P) 
 
 Iron (Fe) 
 
 Calories per 100 g 79 
 
 48 
 
 10 
 
 30 
 005 
 018 
 00034 
 
 In a study of the nutritive values of Hawaiian fruits by the 
 Hawaii Experiment Station, it was noted that the passion fruit 
 has a comparatively high sugar content and is low in calcium, phos- 
 phorus, and iron. 
 
 Hare and his coworkers (7, p. 111$) state that several species of 
 Passiflora have some medicinal value, but give nothing on this 
 
 3 Fruit pulp without seeds and juice, which consists of a few thin skins, not determined. 
 
THE EDIBLE PASSION FRUIT IN HAWAII 5 
 
 point beyond the fact that an alkaloid had been reported. Merck's 
 Index (10, p. 385) states that the dried flowering and fruiting tops 
 of P. incarnata contain an alkaloid in small quantities. 
 
 PASSION FRUIT JUICE 
 
 Investigations as to the possibilities of extracting the juice of 
 passion fruit and demands for the product on the local market 
 have recently been made. 
 
 During the past 5 years, a number of experiments have been 
 made in juice extraction by George Mellen of Honolulu, one of the 
 station's cooperative growers. Tests with various kinds of extracting 
 apparatus were made with both the purple passion fruit (Passiflora 
 < dulis) and the yellow passion fruit (P. cdulis flavicarpa). Some 
 improved apparatus was made for the purpose. 
 
 In 1933 and 1934, when the experimental passion fruit plantings 
 at the Kona substation were beginning to produce fruit, Mr. Mellen's 
 cooperation was secured in studies of extraction and marketing of 
 juice. In addition to these data, Mr. Mellen also made available to 
 the station records of his previous work in processing passion fruit 
 from various localities in the Territory. Table 1 was prepared from 
 these reports. 
 
 Table 1. — Results of extraction of juice from tiro varieties of Passiflora cdulis 
 
 Variety of passion fruit 
 
 Date juice 
 extracted 
 
 Fruits 
 
 Weight of fruit 
 
 Average 
 
 juice per 
 
 fruit 
 
 Total yield 
 
 Total 
 
 Average 
 
 of juice 
 
 
 Aug. 5, 1933 
 Aug. 24,1933 
 
 Number 
 lib 
 lib 
 
 Ounces 
 1, 240. 00 
 1,354.25 
 
 Ounces 
 1.60 
 1.75 
 
 Fluid 
 ounces 
 0.3716 
 .8300 
 
 Fluid 
 ounce* 
 288.00 
 
 
 643. 25 
 
 
 
 Results of an attempt to market the juice were as follows : 
 
 Six gallons of passion fruit juice, approximately 48 pounds, made 
 13.7 gallons of soda-fountain sirup, which sold for $2.40 per 
 gallon $32. 8S 
 
 Cost of transportation, processing of fruit, materials, labor, 
 
 etc $15. 50 
 
 Grower's central expense, 30 percent 9.86 25.36 
 
 Return to grower 7. 52 
 
 No doubt a saving could be made if regular factory methods were 
 established on a large scale and the grower could cultivate larger 
 areas near the factory by improved methods. 
 
 Sales of the juice were rapid and the demand for more has ex- 
 ceeded the local supply. 
 
 GENERAL CULTURAL REQUIREMENTS 
 
 Most of the edible passion fruits grown in Hawaii are indigenous 
 to tropical countries but some of them are now cultivated in such 
 frostless sections of the Temperate Zones as are free of any con- 
 siderable variation of daily temperatures. Unusually cool nights 
 during the active growing season are very detrimental. In Hawaii, 
 
HAWAII EXPERIMENT STATION 
 
 the purple passion fruit and the sweet granadilla or waterlemon 
 have become a part of the natural vegetation in the damp woods of 
 practically all of the larger islands at altitudes ranging from 500 
 to 3,000 feet. In open forests, they spread over the treetops and 
 often yield large crops of fruit. 
 
 SELECTION OF SITES AND SOILS 
 
 Several of the chief localities where the purple passion fruit thrives 
 are a portion of the north slope of Mount Haleakala on the Island 
 of Maui ; parts of the districts of Hilo, Hamakua, and Kona on the 
 Island of Hawaii; eastern slopes of the Waianae mountains on 
 Oahu; and in the Kokee section of the mountains of the Island of 
 Kauai. In the last-mentioned place, the crops are often large and 
 much of the fruit is eaten by wild hogs. The mountain soils of 
 this comparatively cool, moist locality are made up of decomposed 
 lavas which have a liberal incorporation of humus from the forest, 
 and with good drainage, form a very suitable growing medium for 
 the natural growth of this exotic species. 
 
 In selecting a site for passion fruit culture, the grower should 
 have in mind the species or variety to be grown. Both the purple 
 passion fruit and the sweet granadilla or waterlemon will fruit 
 freely up to an altitude of 3,000 feet, but on account of unsatisfac- 
 tory pollination habits, the yellow variety of P. edulis requires lower 
 altitudes, where the air is warm and comparatively dry, in order 
 that cross-pollination may be brought about by insects and sea 
 breezes (p. 2). If possible, the site for growing any kind of edible 
 passion fruit should be of such exposure as to allow the rows of 
 plants to extend from north to south, that both sides may get ex- 
 posure to the sun daily at blossom time. Where irrigation is re- 
 quired, it may be necessary to arrange the rows somewhat differently. 
 
 None of the edible species of Passiflora growing at the Hawaii 
 Experiment Station appear to be exacting in their soil requirements. 
 The soil may vary greatly in texture and composition. Sufficient 
 moisture and humus are the chief essentials. Wet or sour soils, 
 which usually result from lack of underdrainage, are unsuitable. 
 Passion fruit plants will withstand considerable drought, but 
 growth is greatly retarded and productiveness reduced. Altitude 
 is not so important from the standpoint of growth and prolificness 
 as is good culture in a moist and fertile soil. In Hawaii, it is usually 
 easier to select a moist and fertile soil at altitudes between 500 and 
 2,000 feet than to get the required cultural conditions on tillable 
 land below 500 feet. 
 
 PROPAGATION 
 
 Passiflora plants require considerable growth before they are set 
 in the field. The plants may be grown from seeds or cuttings. Most 
 growers, however, propagate from seeds. The seed should be selected 
 from the fruit of good quality, particularly such fruit as is free of 
 fungus diseases. Although no serious passion fruit diseases have been 
 observed or reported in Hawaii, the " brown spot " Macrosporium sp. 
 (IS) is a plant disease of considerable concern to passion fruit 
 growers in parts of Australia, and it is possible that this and several 
 other passion fruit diseases may be transmitted by the seed (3, p. 
 668). 
 
THE EDIBLE PASSION FRUIT IN HAWAII ' 7 
 
 The soft fruit pulp and juice are easily removed from the seeds 
 after soaking in water for 24 hours. After being washed clean, the 
 seeds are dried in the shade sufficiently to prevent the growth of mold, 
 then stored in an air-tight container until needed. The seeds, even 
 when properly stored, lose their viability rapidly after the first year. 
 In fact, they give the best germination if planted soon after having 
 been removed from the fruit. At the Hawaii Experiment Station, 
 they are usually germinated in an ordinary propagating box about 
 14 by 20 inches and 3 inches deep, which will accommodate about 260 
 seeds. 
 
 Ordinary potting soil is generally used. It is gently pressed down 
 to an even surface and the seed are scattered over it at about 1 
 inch apart, then pressed with the flat surface of a block of wood 
 about 1 by 4 by 8 inches, such as is commonly used in propagation 
 work, and then covered with one-half inch of soil and firmed again. 
 The box is labeled with name and date and then set in partial shade 
 where it will get plenty of light, warmth, and fresh air. With a 
 liberal watering to keep the soil damp, germination will take place 
 in 3 to 4 weeks. After reaching a height of about 2 inches, the 
 seedlings are transferred individually to 4-inch plant pots for further 
 growth. After about 2 weeks in a partially shaded place, the seed- 
 lings may be placed on benches outside in full sunlight. In 3 or 4 
 months' time, the plants will be from 6 to 10 inches high and may be 
 set in permanent place in the field. Winter or spring planting is 
 satisfactory in Hawaii and makes but little difference in time of 
 fruiting. Winter planting, however, generally gives larger plants. 
 
 Raising of young plants in containers, in preference to the open 
 nursery, avoids some loss in transplanting and produces a sun- 
 hardened plant which makes more rapid growth in the field. In some 
 countries the seedlings are germinated in nursery beds and when 
 of sufficient size transplanted to the field. In Hawaii, conditions are 
 generally such that the pot -grown methods of developing the young 
 plants prove best. 
 
 SOIL PREPARATION 
 
 Thorough preparation of the land is very important for passion 
 fruit culture. It should be cleared of all undesirable vegetation, 
 stones, and the like and the soil deeply and thoroughly plowed and 
 harrowed to as near a perfect tilth as possible. This gives a greater 
 growing medium in which the passion fruit plants may develop ac- 
 tive roots. It also increases the available plant food and insures bet- 
 ter drainage. In the preparation of the soil, as in the cultivation 
 to be done later, considerable organic matter, such as barnyard ma- 
 nure, panicum grass, old straw, and leguminous plants, may be worked 
 into the soil to improve and maintain fertility. 
 
 TRELLISES AND PLANTING 
 
 Previous to setting the plants, the prepared field should be marked 
 off in rows 10 feet apart and the trellises erected. Some growers 
 find more time for making the trellises after the plants are set ; how- 
 ever, this method is more difficult because care must be taken to avoid 
 injuring the young plants. 
 
 There are several forms of trellises, the most satisfactory consisting 
 of hardwood posts 8 feet long, set 2 feet in the ground at 15 feet apart 
 
8 
 
 in the row. Soft redwood posts are unsatisfactory as they are often 
 seriously damaged by carpenter bees. The posts should be substan- 
 tially braced at the ends of the rows and at about every 200 feet in 
 the row. Each post should have a crosspiece of strong wood 2 by 4 
 inches and 2 feet long, spiked on near the top for the support of two 
 no. 8 galvanized wires which are strung tightly above and stapled, 
 one near each end of the top edge of the crosspiece, so as to form 
 horizontal, parallel lines about 2 feet apart (fig. 1). 
 
 The seedlings are set midway between the posts in the rows at 
 about 15 feet apart. In doing this, each plant is taken from its con- 
 tainer without disturbing the soil on the roots and set in the moist 
 earth of the field. Several weeks after transplanting, each will begin 
 to develop several vigorous branches from near the ground, and 
 
 Figure 1. — The purple passion fruit {Passiflora edulis) in field culture rest at the Kona 
 
 substation. The vines are set at 10 feet apart in rows and trained on trellises con- 
 sisting of two heavy wires supported at 22 inches apart on crossbars of the posts. 
 
 these are allowed to reach several feet in length. The strongest 
 one is then tied up to a temporary stake connecting with one of the 
 wires above and the remaining branches of the plant cut away 
 so that all of the plant food, absorbed by the root system, may be 
 utilized by the remaining stem to produce a vigorous growth. "When 
 this growth extends to a few inches above the trellis, it is tied to 
 one of the wires and the terminal bud cut off to force lateral 
 branches. Only two are allowed to develop at this point, one reach- 
 ing to each wire where it may divide again, spreading both ways 
 and developing fruiting branches at intervals of about a foot. These 
 branches are trained alternately over the wires and allowed to hang 
 down. This arrangement distributes the weight of the vine over 
 the two wires, utilizes all of the space between posts, and tends to 
 give a comparatively open top for the circulation of air and the 
 penetration of sunlight. 
 
THE EDIBLE PASSION FRUIT IN HAWAII \) 
 
 TILLAGE 
 
 The passion fruit field should be kept clean and free of weeds at 
 all times. This is done mainly with the cultivator and harrow. 
 Shallow cultivation is necessary in order to avoid injury to the root. 
 The disk cultivator and disk harrow are best for this purpose. Deep 
 plowing is not advisable except in the preparation of the land in 
 the beginning and before resetting the field with new plants. The 
 shallow cultivation also keeps the surface open for aeration and in 
 a condition to retain the greatest amount of rainfall with the aid 
 of the mulch turned under by the deep plowing at the time of the 
 preparation of the field for planting. 
 
 Short-period crops of garden vegetables can be grown in the 
 middle portion of the spaces between rows during the first year. 
 
 FERTILIZERS 
 
 The passion fruit species, which are heavy bearers, are naturally 
 heavy feeders. The well-prepared field may be sufficiently rich in 
 plant food for the first year or two but if the soil is very poor it 
 should be fertilized before planting. 
 
 In the passion fruit experiments barnyard manure was applied 
 previous to setting the plants, and this was followed by two appli- 
 cations of a complete fertilizer prepared especially for fruit-produc- 
 ing plants. This fertilizer contained 5 percent of nitrogen. 6 of 
 phosphorus, and 3 of potash, with some calcium in the compounds 
 carrying the 2 latter elements. The first application was 1 pound 
 per plant, and the second, applied about 4 months later. 2 pounds 
 per plant. These amounts should be increased considerably in the 
 second, third, and fourth years, when heavy crops are expected . 
 
 Reports giving recommendations in reference to use of fertilizers 
 for the passion fruit in Australia (-i, p. 673) and several other 
 countries indicate the use of a complete fertilizer similar to that 
 used in the Hawaiian experiments. 
 
 PRUNING 
 
 Where the tops of the vines become too dense, portions may be 
 pruned out at certain seasons. This is best done when the plants are 
 beginning vigorous growth. Pruning during periods of dormancy 
 has proved unsatisfactory, particularly if considerable portions of 
 the vines are removed. In pruning, all dead leaves and branches 
 should be removed, as well as interfering branches, which would 
 tend to produce an unfruitful condition. Clipping excessively long 
 branches tends to force a number of short-fruiting laterals on the 
 remaining portions. Barnes (-i, p. 672) states that pruning is prac- 
 ticed in Australia to bring in the crop at different periods of the 
 year when better prices may be realized. 
 
 INSECT ENEMIES AND PLANT DISEASES 
 
 Insect enemies and plant diseases of the edible passion fruit plant- 
 are not numerous. In Hawaii there is as yet only one serious enemy, 
 the Mediterranean fruit fly. It has attacked the fruit of Passiflora 
 edtdis in some localities at certain seasons, while in others the fruit 
 matures without blemish. The fruit fly punctures are made before 
 
 14415S°— 35 2 
 
10 BULLETIN 7 4, HAWAII EXPERIMENT STATION 
 
 the fruit has matured, apparently when the rind is tender. Further 
 growth deposits a stony mass on the inside of the rind, cutting the 
 puncture off from the pulp inside. No maggots are found in any 
 part of the fruit, and although the stony wall appears to prevent 
 decay it is detrimental as it prevents the development of pulp and 
 seed, sometimes to the extent of more than half the interior of the 
 fruit, and results in very inferior fruit. The fruit fly punctures, 
 which occasionally occur on the yellow variety of P. Edulis, also 
 fail to produce larvae, and the rind, which is thicker and harder 
 than that of other varieties, does not develop the stony obstruction 
 on the inner surface. The damage to this variety is mere disfigure- 
 ment of the outer surface of the fruit. 
 
 No fungus diseases have as yet been reported as attacking either 
 plant or fruit of any of the edible Passifloras in Hawaii. Several 
 serious diseases have caused much concern to growers in some other 
 countries (15^ p. 564), 
 
 HARVESTING AND MARKETING 
 
 The harvesting of the crop is a comparatively easy part of passion 
 fruit production. It is also much less difficult than the handling of 
 most other horticultural crops. The grower of any considerable 
 amount of passion fruit should be either equipped to extract and 
 preserve the juice or be near a market which will take large quan- 
 tities of the fruit regularly. Gathering and handling should be 
 done while the fruit is cool. Fruit intended for shipment to any 
 considerable distance should be cut from the plants when it is just 
 approaching the full color of ripeness. For local markets or imme- 
 diate- use, it may be fully ripened, when the flavor is best. Many 
 growers prefer to let the fruit ripen and fall to the ground, picking 
 it up each morning. 
 
 When the fruit has been gathered, it should be carefully laid in 
 padded field boxes of about 12 by 12 by 18 inches in size. Crinkled 
 and marred fruit does not sell well on the market, although it may 
 be good otherwise. It should be used for local consumption or 
 juice extraction. The juice keeps well and in good condition for 
 the market. Properly ripened passion fruit, like most other fruit, 
 has the best flavor. Fruit intended for market purposes should 
 not be shipped in bags, large boxes, or barrels. The best result in 
 shipping the fruit from the Kona substation to Honolulu, was ob- 
 tained by using strong paper boxes having a capacity of about 20 
 pounds of fruit each. 
 
 In a study of marketing Australian passion fruit, Gregory (5, 
 p. 10) found it highly important to handle the fruit carefully in pick- 
 ing, sorting, and packing, especially when intended for long-dis- 
 tance shipments. He also advises the growers to sort the fruit into 
 three grades as follows : Special — large and medium-sized fruit, full 
 of juicy pulp, and free of dummy, blemished, and diseased fruit; 
 Standard — large and medium-sized, slightly skin-blemished fruit, 
 full of pulp, and free of dummy and diseased fruit; Plain — small- 
 sized fruit and all sizes of crinkled and blemished fruit, free of 
 dummy and diseased fruit. Gregory points out the importance of 
 growers grading the fruit to some such plan as the above, as it en- 
 ables agents and buyers to understand the quality of the fruit they 
 
THE EDIBLE PASSION FRUIT IX HAWAII 11 
 
 are handling. He describes simple equipment for packing and 
 different methods of arranging the fruit in the packing boxes, which 
 makes possible quick determination of size and number of fruit per 
 box. 
 
 USES 
 
 The uses of the passion fruit are numerous. The edible portion 
 of the fruit, consisting of pulp, seeds, and juice, is used in fruit 
 salads. The juice has a very individualistic flavor and is in con- 
 siderable use in making refreshing soda-fountain drinks (2< p. 272). 
 It is also used in making various kinds of cocktails, cordials, jelly, 
 sirup, sherbet, ice cream, flavoring for icing, candy, and cake. 
 
 DESCRIPTIONS OF EDIBLE PASSION FRUITS 
 
 PURPLE PASSION FRUIT 
 
 The purple passion fruit (Passiflora edulis) is native of Brazil, 
 but has spread to many other warm parts of the world where, in 
 moist localities, it often thrives as a part of the natural vegetation. 
 It has been considerably cultivated in Queensland, Australia, where in 
 different localities it is known by such names as purple-fruited grana- 
 dilla, purple passion fruit, and as passion fruit. In India it is also 
 known as the " sweet cup " (fig. 2). 
 
 The purple passion fruit was introduced into Hawaii about 1880, 
 where it soon became known to the Hawaiians as " lilikoi ", a name 
 given presumably from the locality on the Island of Maui where 
 it was first grown. 
 
 There are several strains of the purple passion fruit distinguished 
 mainly by size of fruit, a characteristic which recurs even when 
 propagated by seed. One of these has larger purple fruit than that 
 of the original type, but it has not proven as satisfactory because 
 it is naturally a shy bearer. Another strain is more outstanding be- 
 cause the fruit is larger, of a yellow color, and the pulp and juice 
 are more tart than that of the purple form, believed to be a true 
 species hybrid between the purple and some other species, possibly 
 Passiflora ligularis. It is described as a distinct variety, flavicarpa* 
 in this publication. 
 
 DESCRIPTION 
 
 The woody perennial is a robust climber which, under favorable 
 conditions, may spread over a large treetop 40 or 50 feet high and 
 produce two crops of fruit per year. The seasons of maturity in 
 Hawaii are usually summer and late fall, depending somewhat upon 
 the nature of the season. 
 
 Leaves. — The leaves are alternately arranged, one at each node. 
 The blade is cordate at the base, three-lobed, margin finely serrated, 
 and the upper surface glossy green. The short leafstalk contains 
 two semilunar glands or nectaries on the upper surface near the 
 junction with the blade. 
 
 Flowers. — The flowers are solitary, about 2 inches across, each on a 
 short stalk extending from a leaf axil. Inside and spreading above 
 the whitish petals is the crown or corona composed of two series or 
 rows of threadlike rays which have the basal halves purplish and 
 the outer, white. There are five stamens, each terminating with 
 heavy pollen-bearing anthers, and from the center of the flower ex- 
 
12 BULLETIN 7 4, HAWAII EXPERIMENT STATION 
 
 tends the compound pistil terminating in a three-parted stigma 
 Wed for Pollination by both .md and insects. ^ 
 
 defp p^Te h in f ™oti- S af fud ripeness. Within the hard leathery 
 
 *asi s«\srts asst^usMFss^ war 
 
 rind are numerous small seeds -Ag™%^VtfSSft 
 ^ffi £&??*£ «rtom the plant and the 
 rind shrinks and becomes wrinkled. 
 
THE EDIBLE PASSION FRUIT IN HAWAII 13 
 
 YELLOW PASSION FRUIT 
 
 The yellow passion fruit (Passiflora edtdis favicarpa) 4 is also 
 known by the common name of yellow-fruited lilikoi. Although ap- 
 parently closely related to the purple passion fruit, the two differ 
 considerably. The plant is more vigorous and the flowers are larger 
 and more fragrant, with stronger tendencies toward protandrous 
 habit. 5 The fruit also differs in being of a yellow color at maturity 
 and the flavor of the pulp and juice is more clearly defined. 
 
 The Hawaii Experiment Station first received seed of the yellow 
 passion fruit from the late E. X. Reasoner of Oneco, Fla., in 1923. 
 Mr. Reasoner had obtained the seed in Australia when on a visit to 
 that country. A considerable number of plants were grown by the 
 Hawaii Station in the years following and distributed to growers in 
 various parts of the Territory. 
 
 DESCRIPTION 
 
 The woody perennial vine is very strong when grown in favorable 
 environments. It gives a light crop in about 18 months from seed, 
 and two crops per year, occurring in July and October, with possibly 
 some variation according to environment (fig. 3). 
 
 Leaves. — The leaves are almost identical with those of the purple 
 passion fruit but appear to be a little more vigorous. 
 
 Flowers. — The flowers are similar to those of the purple variety 
 but differ in being larger and more brilliant in color and more fra- 
 grant. They also bear two marginal glands on the outer fourth of 
 the three outside sepals. 
 
 Fruit. — The fruit produced by seedling plants varies in size and 
 shape from spherical to oval. The average fruits vary from 2y 2 to 3 
 inches in greatest diameter : light yellow in color at full ripeness ; rind 
 leathery, *4 mcn m thickness and white beneath the outer surface. 
 The central cavity contains many seeds, each surrounded with a juicy, 
 orange-colored pulp which is quite acid and of a decided aromatic 
 flavor. 
 
 SWEET GRANADILLA OR WATERLEMON 
 
 The sweet granadilla (Passiflora ligularis) has been fairly well 
 known in Hawaii for over 30 years. Wilder (18, p. 2H)* in 1911, 
 stated that the date of its introduction to Hawaii, and by whom, 
 was not known. In parts of the Island of Hawaii, however, it has 
 been growing for many years as a part of the natural vegetation. 
 
 The species was erroneously called P. laurifolm in Hawaii. A 
 more thorough study of its specific characters showed it to be P. 
 ligularis. The common name i; waterlemon '* is also misused, as 
 long ago that name was applied to another species in some English- 
 speaking countries (2, p. 44^/ ^< P- 267) . 
 
 In recent years the sweet granadilla has spread to many locali- 
 ties where there are warm, moist woods adapted to its natural 
 growth (fig. 4). Such conditions usually range from near sea 
 
 4 See footnote 2. 
 
 5 The anthers shed their pollen before the stigmas are in a condition to receive it. 
 and without fertilization of the ovaries there is a failure to set fruit. 
 
14 
 
 BULLETIN 7 4, HAWAII EXPERIMENT STATION 
 
 level to about 3,000 feet in altitude. In season— July, August, and 
 possibly September— the fruit is frequently on sale in local mar- 
 kets and sells for a fair price. The fruit is of good quality when 
 fresh, and is wonderfully refreshing when eaten out of hand in the 
 
 Figure ... — Ihe yellow passion fruit (Passiflora editlis fiavicarpa) is very exacting in its 
 requirement but is tbe favorite passion fruit of tbe sunny, dry localities at lower 
 altitudes in Hawaii. 
 
 wild, but soon deteriorates after being picked. Its main use is as 
 a dessert fruit. The fruit is grown to some extent in its native coun- 
 tries, Mexico and parts of Central America, and meets with con- 
 siderable favor in the markets of these countries. 
 
THE EDIBLE PASSION FRUIT IN HAWAII 
 
 15 
 
 DESCRIPTION 
 
 The plant is a perennial, propagated mainly by seeds and climbs 
 by means of tendrils. Under good conditions, it is a vigorous 
 climber, and when allowed to run wild, spreads over trees, fences. 
 
 FiGDBB 4.— The sweet granadilla (Passiftora ligularis) -rows freely as a wild climber 
 of the cool, moist woodland in Hawaii where the fresh, delicious fruit is highly priced 
 
 and buildings, but is easily confined to a trellis when grown in cul- 
 tivation. It is valuable not only for its fruit, but its foliage and 
 flowers are ornamental. The steins are smooth, slightly woody at 
 the base. - o 
 
16 
 
 Leaves. — The leaves are large, light green, heart-shaped, and with 
 entire margins. The leafstalks bear three pairs of ligular glands, 
 i. e., glands mounted on ligules or strap-shaped stalks, hence its 
 specific name ligularis. 
 
 Flowers. — The flowers have a sweet musklike odor. They are 
 usually solitary, 3 inches across; sepals and petals greenish; the 
 corona white with zones of white and purple. 
 
 Fruit. — The fruit is oval or slightly elliptical in form 5 about 3 
 inches long, and of an orange-brown or sometimes partially purple 
 color and with numerous whitish specks. The shell is firm enough 
 to make it possible to ship the fruit long distances without injury. 
 The seeds are numerous, and each is surrounded with a light-col- 
 ored, juicy pulp, which, with the seeds, is the edible portion hav- 
 ing a pleasing subacid flavor and pleasant odor. 
 
 GIANT GRANADILLA 
 
 This species of passion fruit (Passiflara quadrangularis) is native 
 of the Tropics of South America. It is now widely distributed 
 throughout the warm, moist parts of the earth, where it is grown 
 as an ornamental and for its edible fruit. The giant granadilla has 
 several other names, such as " common granadilla ", the " granadilla 
 vine ", and the " square-stalked passion flower ", according to Ochse 
 (11, p. 101). The word "granadilla" is from the Spanish and is 
 applied in different parts of the Tropics to several other species of 
 Passiflora, all of which have less robust vines and comparatively of 
 smaller fruit. The species name quadrangularis has reference to the 
 four-angled stems (fig. 5). There are several strains varying mainly 
 in size of fruit. Formerly the strain with the largest fruit was 
 believed to be a different species and was botanically named P. 
 macrocarpa, but investigation has shown lack of sufficient specific 
 characteristics and the name is now given as synonymous with P. 
 quadrangularis by Bailey (2, P- 445). Popenoe (IS, p. 247) recog- 
 nizes a form which has foliage blotched with yellow. 
 
 The ripe fruit of the giant granadilla makes a wholesome delicacy 
 by mixing pieces of the white, semisolid portion of the rind with the 
 juicy, purple pulp from around the seeds and serving with sugar 
 and cracked ice (11, p. 102). When fully ripened the giant grana- 
 dilla is one of the most highly flavored tropical fruits. It is eaten 
 either alone or used in combination with papaya, pineapple, and 
 banana, and with the juice of lemon or lime to form a fruit salad. 
 It may be used in making sherbets. Macmillan (0, p. 268) states 
 that both the preripe fruit and the root, which is usually fleshy, are 
 cooked and eaten as vegetables. Other uses of the fruit have been 
 reported (14, p. 55). 
 
 The methods of propagation are similar to those used for all 
 species of Passifora bearing edible fruit (p. 6). 
 
 The giant granadilla is quite exacting in its requirements. For 
 successful growth it requires a deep, fertile, well-drained soil and a 
 comparatively warm temperature, varying but little from day to 
 night. In Hawaii it is occasionally found in home gardens up to 
 altitudes of about 1.500 feet. In parts of India it is reported to be 
 in cultivation up to 3,000 feet, and it is also grown to a considerable 
 
THE EDIBLE PASSION FRUIT IN HAWAII 
 
 17 
 
 extent in the Dutch East Indies, where in some particularly favorable 
 areas it grows wild as an escape. For good growth each plant should 
 have a space 8 to 10 feet across, and in field culture the plants should 
 
 Figure 5. — The giant granadilla {Passiflora quadrangulai 
 
 vine with lame leaves and fruit, the edible fruit often 
 as much as 8 pounds. 
 
 Is I is a coarse, angular-stemmed 
 to 10 inches long and weighing 
 
 be set in rows 8 or 10 feet apart each way and trained on rather 
 open overhead trellises, which will give a horizontal spread at 6 or 
 7 feet above the ground, allowing the fruit to hang suspended be- 
 neath and have both space and protection for natural growth. 
 
18 BULLETIN 74, HAWAII EXPERIMENT STATION 
 
 DESCRIPTION 
 
 The plant is a coarse perennial with a more or less fleshy root, 
 woody stem, and green four-angled branches. It climbs by means 
 of tendrils. 
 
 Leaves. — The leaves are alternately arranged, 6 to 8 inches long, 
 yellowish green, ovate or elliptical, cordate at base and margin 
 entire; leafstalk angular, contains 3 pairs of nectaries or glands, and 
 the stipules are relatively broad. 
 
 Flowers. — The flowers are very attractive in color and fragrance; 
 4 to 5 inches across; flower stalk short and bearing 3 large green 
 bracts near the base of the receptacle ; calyx segments 5, broad, thick, 
 spongy, greenish outside and white or pinkish within; petals 5, red 
 above, white or pinkish below; corona (a crownlike structure) con- 
 sisting of 4 or 5 whorls or circular rows of rays, the 2 or 3 inner 
 whorls very short and white blotched with red, 2 outer rows con- 
 sisting of coarse stringlike rays forming a fringe, reddish at the 
 base, the remainder cross striped with purple and white, and the 
 outer halves of the ra} T s more or less crooked from having been 
 folded in the bud; stamens 5, rising above the central column, an- 
 thers broad and pivoted on the filament from the upper side. The 
 ovary of the pistil is mounted on a gynaphore (a stalk raising the 
 pistil above the stamens) and the style is divided into 3, sometimes 
 4 or 5 parts, each of which terminates into a rather large, globular 
 or reniform stigma. 
 
 Fruit. — The fruit is oval-oblong or elliptical, 9 or 10 inches long, 
 often weighing 4 or 5 pounds; skin thin, light green or yellowish 
 green when ripe; rind about 1% inches thick, central cavity con- 
 taining many seeds, each surrounded with a subacid purplish or 
 yellowish, juicy pulp of pleasing flavor. Seeds flattish oval in 
 outline, three-eighths inch long and of a brownish color. 
 
 BELL-APPLE 
 
 The bell-apple {Passiflora laurifolia) (fig. 6) has several other com- 
 mon names, as " sweet-cup ", " waterlemon ", " Jamaica honeysuckle ", 
 " Pomrae d'or ", and some have called it the " yellow granadilla fruit " 
 (13, p. 2Jf8) . These names tend to cause confusion. The entire, ellip- 
 tical leaves, unusual for Passiflora, are somewhat like those of the 
 well-known laurel which was probably the guide for the specific name, 
 as given by the botanist Linnaeus, who named it. 
 
 DESCRIPTION 
 
 The bell-apple plant is a handsome and moderately vigorous 
 climber which is most valuable for covering unsightly structures. Its 
 bright green foliage, beautiful flowers, and pendular. golden fruit are 
 very ornamental. In Brazil and parts of the West Indies, where it is 
 apparently indigenous, it is cultivated mainly for the fruit, which 
 has an agreeable subacid flavor. The plants are easily propagated by 
 seeds and by cuttings. In Hawaii, as in India and Ceylon, the plants 
 blossom freely but mostly drop without setting the fruit, possibly be- 
 cause of insufficient pollination (9, p, 267). 
 
THE EDIBLE PASSION FRUIT IN HAWAII 
 
 19 
 
 Leaves. — The vine is a glabrous climber with alternately arranged 
 elliptical or long-elliptical leaves, each with pointed apex, entire mar- 
 gin, 6 to 8 inches long, and with a single pair of petiole glands near 
 the point of attachment with the base of the leaf blade. 
 
 Figure 6. — The bell-apple (Passiflora laurifolia) is an attractive arbor vine — the foliage, 
 flower, and edible fruit are very ornamental. It is interesting to note that the bright 
 orange-colored fruit is unusual in being surmounted with three rich green bracts. 
 
 Flowers. — The large, handsome, fragrant flowers are 3 to 4 inches 
 across. They contain a beautiful arrangement of green, white, pink, 
 red, and violet tints. 
 
20 
 
 BULLETIN 7 4, HAWAII EXPERIMENT STATION 
 
 Fruit— The fruit is ellipsoidal, orange-yellow, 2.5 inches long and 
 unusual in being surmounted by three large green bracts. The rind 
 or soft shell surrounds a white spongy covering of the edible portion 
 which consists of juicy pulp and seeds. 
 
 Figure 7. — The sweet calabash (Pa&siflora maHformis) is very ornamental. The hard 
 rind of the edible fruit is difficult to open. The species is said to have particular value 
 in crossbreeding work. 
 
 SWEET CALABASH 
 
 The sweet calabash is botanically known as Passiflora maliformis 
 Linn. Popenoe (13, p. 21$) states that it is native of tropical 
 America where it is called " curuba " or " kuruba ", and that it is 
 
THE EDIBLE PASSION FRUIT IN HAWAII 21 
 
 cultivated in the West Indies and Colombia. Wester (16, p. 7) re- 
 ports its cultivation in Brazil and Ecuador for its aromatic, palatable 
 pulp. Grisebach (6, p. 293), who made a considerable study of 
 Passiflora, describes the species botanically and gives its habitat 
 as the West Indies and Xew Granada. 
 
 The common English name probably originated from the nature 
 of its fruit, the outer covering of which is hard like the shell of a 
 gourd, and the specific name maliformis also has reference to the 
 fruit, which is shaped like the common apple (Pyrus mains). 
 
 DESCRIPTION 
 
 In Hawaii the species has been grown in private gardens mainly 
 for ornamental purposes for which it is conspicuously suited. Each 
 bud is enclosed in a large bladdery covering formed by the three 
 bracts, which, upon blooming, open and form a cream white back- 
 ground for the more highly colored floral parts (fig. 7.) The Hawaii 
 Experiment Station is cultivating it for use in plant-breeding work 
 because the species has very prolific habits and is apparently quite 
 immune to the attacks of certain insect pests and plant diseases 
 known to infest some other passion fruit plants. It may be possible 
 to develop a hybrid having these resistant qualities and a better 
 fruit. The comparatively small size and hard shell of the sweet 
 calabash are objectionable characters, particularly when the fruit 
 is in competition with other species and varieties already being grown 
 in Hawaii. 
 
 Leaves. — The vine of the sweet calabash is relatively small and 
 slender. The leaves are from 4 to 6 inches long, ovate to ovate- 
 oblong, with an apex which terminates in a small, sharp, recurved 
 point ; leafstalk biglandular above the middle. 
 
 Flowers. — Tendrils and flowers arise from the axils of leaves, 
 flower stalk slim, flowers about 4 inches across, attractively marked 
 with tints of white, purple, and blue ; sepals prominently keeled be- 
 hind, light green, and dotted with reddish brown in front; petals 
 rudimentary and essential organs (stamens and pistils) very similar 
 to those of other passion fruit flowers. 
 
 Fruit. — The fruit is oval, 1.75 inches long, light green turning to 
 brownish at full maturity and rind hardening into a shell: seeds 
 small, flat, and surrounded with a grayish juicy pulp of subacid 
 flavor. 
 
LITERATURE CITED 
 
 (1) Anonymous. 
 
 1932. passion fruit growers cash in. Calif. Cult. 78(12) : 272. 
 
 (2) Bailey, L. H., and Bailey, E. Z. 
 
 1930. HORTUS; A CONCISE DICTIONARY OF GARDENING. GENERAL HORTICUL- 
 TURE AND CULTIVATED PLANTS IN NORTH AMERICA. 652 pp., illUS 
 
 New York. 
 
 (3) Barnes, H. 
 
 1934. passion* fruit culture in Queensland. Queensland Agr. Jour. 41 : 
 667-675, illus. 
 
 (4) Degener, O. 
 
 1932-33. flora hawaiiensls. Book 1 (looseleaf), illus. Honolulu. 
 
 (5) Gregory, J. H. 
 
 1932. marketing passion fruit. Queensland Agr. Jour. 38 : 43-61, illus. 
 
 (6) Grisebach, A. H. R. 
 
 1864. FLORA OF BRITISH WEST INDIAN ISLANDS. 789 pp. London. 
 
 (7) Hare, H, A., Caspari, C, Rusby, H. R., Geisler, J. F., Krkmers, E., and 
 
 Base, D. 
 
 1905. THE NATIONAL STANDARD DISPENSATORY. CONTAINING THE NATURAL 
 HISTORY, CHEMISTRY, PHARMACY, ACTIONS AND USES OF MEDI- 
 CINES . . . I860 pp., illus. Philadelphia and New York. 
 
 (8) HlLLEBRAND, W. 
 
 1888. FLORA OF THE HAWAIIAN ISLANDS : A DESCRIPTION OF THEIR PHANER- 
 OGAMS and vascular cryptogams. Annotated and publ. by 
 W. F. Hillebrand. 673 pp., illus. London and New York. 
 
 (9) Macmillan, H. F. 
 
 1925. TROPICAL GARDENING AND PLANTING, WITH SPECIAL REFERENCE TO 
 
 ceylon. Ed. 3, 617 pp., illus. Colombo. 
 
 (10) Merck & Co., Inc. 
 
 1930. MERCK'S INDEX; AN ENCYCLOPEDLA FOR THE CHEMIST, PHARMACIST, 
 
 and physician. Ed. 4. 585 pp. New York, Philadelphia, [etc.] 
 
 (11) Ochse, J. J., in collaboration with Bakhuizen van dan Brink, R. C. 
 
 1931. FRUITS AND FRUITICULTURE IN THE DUTCH EL\ST INDIES. 180 pp., 
 
 illus. Batavia. 
 
 (12) Pope, W. T. 
 
 1934. PROPAGATION OF PLANTS BY CUTTINGS IN HAWAII. Hawaii Agl*. 
 
 Expt. Sta. Circ 9, 35 pp., illus. 
 
 (13) POPENOE, W. 
 
 1924. MANUAL OF TROPICAL AND SUBTROPICAL FRUITSi, EXCLUDING THE 
 BANANA, COCONUT, PINEAPPLE, CITRUS FRUITS, OLIVE,, AND FIG. 
 
 474 pp., illus. New York. 
 
 (14) Queensland Department of Agriculture, Fruit Branch. 
 
 1931. passion fruit culture!. Queensland Agr. Jour. 36:51-55, illus. 
 
 (15) Simmonds, J. H. 
 
 1930. brown spot of the passion fruit vine. Queensland Agr. Jour. 
 
 34: 564-585, illus. 
 
 (16) Wester, P. J. 
 
 1931. edible passion fruit. Chamber Com. [Manila] Jour. 11(2) : 7. 
 
 (17) Westgatei, J. M. 
 
 1930-34. REPORTS OF THE HAWAII AGRICULTURAL EXPERIMENT STATION, 
 
 1929-33. 
 
 (18) Wilder, G. P. 
 
 1911. FRUITS OF THE HAWAIIAN ISLANDS. Rev. ed., 247 pp., illUS. 
 
 Honolulu. 
 22 
 
 U.S. GOVERNMENT PRINTING OFFICE: 1935