•s? % o \0 *o " a b .^^ ' -' ^0* .o v & * „ „ " . vP S ,v ^ .,0' w fc w -*1 V** -, : 0^ c»"S ^O ^1 */" v,^ v .* ■V ^ •d« \ A O A. ^ V ^0^ r* 7 * %. . vV . 5 * « r . ^> 4 Ube mntverstts of Gbtcaao THE ZOOCECIDIA OF NORTHEASTERN UNITED STATES AND EASTERN CANADA A DISSERTATION SUBMITTED TO THE FACULTY OF THE OGDEN GRADUATE SCHOOL OF SCIENCE IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF BOTANY BY BERTRAM WHITTIER WELLS Private Edition, Distributed By THE UNIVERSITY OF CHICAGO LIBRARIES CHICAGO, ILLINOIS Reprinted from The Botanical Gazette, Vol. LXV, No. 6 June, 1918 Ube mniversttE of dbtcaao THE ZOOCECIDIA OF NORTHEASTERN UNITED STATES AND EASTERN CANADA A DISSERTATION SUBMITTED TO THE FACULTY OF THE OGDEN GRADUATE SCHOOL OF SCIENCE IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF BOTANY BY BERTRAM WHITTIER WELLS Private Edition, Distributed By THE UNIVERSITY OF CHICAGO LIBRARIES CHICAGO, ILLINOIS Reprinted from The Botanical Gazette, Vol. LXV, No. 6 June, 1918 i sity THE ZOOCECIDIA OF NORTHEASTERN UNITED STATES AND EASTERN CANADA CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 239 B. W. Wells This summary is based upon a completed descriptive account 1 of the zoocecidia of the region studied, which is that phy to- geographic region dealt with by Gray's New Manual of Botany (7th ed., 1908). The only similar general statement preceding this is that of Felt (4), who has presented some approximate figures from an entomological standpoint pertaining to American insect galls. The mite (Eriophyidae) galls were not included in his discussion. Historical Three local studies of zoocecidia have been made which deserve mention in a brief historical account. Cook (2) in 1904 published the description of 66 galls from Indiana. Jarvis (7) in 1908 presented a catalogue of the insect galls of Ontario, comprising 221 species. Stebbins (10) in 1910 described 205 species of galls collected in the vicinity of Springfield, Massachusetts. A post- humous catalogue of 233 southern New England galls by Thompson (11) appeared in 1915, edited by Felt. This also included a summary of American Cynipidae galls, listing 350 species. For the sake of comparison a short summary of the European work will be given. Haimhoffen (5) in 1858 presented 350 as the number of zoocecidia for central Europe. Schlechtendal (9) in 189 1 listed 13 15 insect, mite, and nematode galls on the plants of Germany. Kieffer (8) in 1901 published a synopsis of the zoocecidia of Europe. There also appeared the same year a more exhaustive study in Darboux and Houard's (3) systematic 1 The work contains the description of 792 nematode, mite, and insect galls; half of this number will be supplemented by illustrations. Keys to the galls on the various plant genera have been made, the plant genus constituting the unit by which the galls have been grouped. 535] [Botanical Gazette, vol. 65 536 BOTANICAL GAZETTE [juxe catalogue of the zoocecidia of Europe and the basin of the Mediter- ranean, a work which in 1908 (supplement 19 13) was expanded by Houard (6) into the largest systematic cecidological work in exist- ence. This final general European work comprises the description of 1950 zoocecidia. Basis and plan of work The data from which the following summary is drawn were obtained during a period of 4 years, in which field studies in Con- necticut, Ohio, and Kansas were supplemented by a thorough canvass of the highly scattered cecidological literature. It may be of interest to mention the simple' and, it is believed, practical scheme which has been followed in the arrangement of the 792 types described. The plant genus was made the unit under which the galls were grouped. This is in contrast to Houard's plan; he used the species, a plan which necessitated a vast amount of repetition, since innumerable galls occur on more than one species within the genus. It is a striking fact that very few galls are found upon more than one genus. In the study of the galls of the north- eastern United States, data concerning the plant species bearing the gall have been included with the descriptive material. To assist in locating the descriptions, keys were worked out for the genera having more than 6 or 8 species. A brief bibliography presenting the most important references was appended to each description. The plant genera in the work have been arranged alphabetically. The galls under each genus have been aggregated according to the classification of the cecidozoons. It is thus evident that artificial classification has been pursued throughout. At the present time any classification of zoocecidia must be artificial. The morpholog- ical data available, particularly of an anatomical nature, are far too meager to make possible anything approaching a natural classification. Summary of numerical data In the case of all of the following figures presented, it should be understood that they are but approximations. So new is the field of systematic zoocecidology in America, and so incomplete and 1918] WELLS—ZOOCECIDIA 537 unsatisfactory are the data in innumerable specific instances, that at the present time any generalizations of a numerical nature cannot be accepted as expressing the exact condition. A tabulated statement of the 792 galls known from the north- eastern quarter of the United States and eastern Canada, according to the cecidozoon orders and families, is as follows: DISTRIBUTION BY ANIMAL FAMILIES Nematoidea (Nematohelminthes) Gelechiidae 3 Anguillulidae 2 Elachistidae 2 Acarida (Acarina) Sesiidae 1 Eriophyidae 87 Tortricidae 2 Hemiptera (Insecta) Unclassified 10 Aphididae 70 Diptera Psyllidae 6 Trypetidae 7 Jassidae . 1 Itonididae 383 Coleoptera Hymenoptera Cerambycidae 2 Chalcidae 2 Buprestidae 1 Tenthridinidae 13 Lepidoptera Cynipidae 194 Tineidae 1 As Felt has pointed out, the family containing the most gall makers is the Itonididae, embracing in our region 47 per cent of the gall biota. The Cynipidae follow with 37 per cent. The other families are represented by much smaller percentages, the Coleop- tera being barely represented with 3 ill-defined galls. The distribution of the galls (except nematode) by the plant families on whose members they occur is as follows. The families are arranged in the sequence given in Gray's Manual. DISTRIBUTION BY PLANT FAMILIES Pinaceae 13 Aristolochiaceae 2 Rosaceae 70 Typhaceae 1 Polygonaceae 2 Leguminosae 18 Gramineae 5 Chenopodiaceae 5 Euphorbiaceae 4 Cyperaceae 1 Nyctaginaceae 1 Anacardiaceae 10 Juncaceae 1 Portulacaceae 1 Aquifoliaceae 1 Liliaceae 9 Ranunculaceae 7 Celastraceae 1 Iridaceae 1 Magnoliaceae 2 Aceraceae 14 Salicaceae 60 Lauraceae 5 Balsaminaceae 3 Juglandaceae 64 Papaveraceae 1 Rhamnaceae 2 Betulaceae 18 Cruciferae 1 Vitaceae 20 Fagaceae 183 Saxifragaceae 5 Tiliaceae 7 Urticaceae 37 Hamamelidaceae 7 Malvaceae 1 538 BOTANICAL GAZETTE [June DISTRIBUTION BY PLANT FAMILIES — Continued Hypericaceae 2 Ericaceae 17 Labiatae 14 Violaceae 2 Primulaceae 1 Solanaceae 3 Cactaceae 1 Ebenaceae 2 Scrophulariaceae 2 Lythraceae 1 Oleaceae 6 Bignoniaceae 1 Onagraceae 1 Apocynaceae 1 Rubiaceae 3 Araliaceae 1 Asclepiadaceae 2 Caprifoliaceae 16 Umbelliferae 1 Convolvulaceae 1 Compositae 121 Cornaceae 1 1 Verbenaceae 3 The striking fact brought out by this list is the extreme irregu- larity of the distribution. Many of the larger families have few or no galls, while on the other hand a few of the smaller families, particularly the Fagaceae, possess many cecidia. Quercus alone has 176 galls, of which 157 are cynipid types. Felt presents 277 as the approximate figure for the cynipid galls on the American oaks. The Cynipidae- Quercus situation in Europe as well as in America presents the most striking example of gall evolution within a single genus of plants related to a comparatively few (9 or 10) closely related genera of insects. It is worthy of note that such large families as the Caryophyl- laceae, Cruciferae, and Boraginaceae contain no gall-bearing species. The Umbelliferae possess but a single gall. The widely distributed tree species Platanus occidentalis does not bear any zoocecidia. The problem in distribution on the plants presented by the preceding list is an exceedingly difficult one and probably cannot be answered on the basis of the physiological information at present available. This intimate and constant relation between specific insects and specific plants forms one of the most significant phenom- ena in the field of cecidology. As far as data were obtainable, figures were worked out indi- cating the distribution of the galls on the plant parts, with the following result: DISTRIBUTION ON PLANT PARTS On leaf blade (of these 52 are "blis- On roots 12 ter" galls) 427 On flowers v . 27 On petiole (most of these occur also From buds forming a rosette type ... 47 on blade) 47 From buds forming a solid concentric On stem (8 per cent of these occur type 3° also on the leaf) 208 1918] WELLS—ZOOCECIDIA 539 Slightly over half of the galls (53 per cent) occur on the leaf blade. This fact is of course related to the relatively large amount of embryonic leaf tissue exposed in the early stages of shoot develop- ment. In the cases of the stem, root, and bud galls numerous factors enter, but perhaps the most important is the factor of insect equipment necessary to place the larval cecidozoon in contact with the meristematic tissues. Some figures pertaining to gall structure were obtained which are of interest. A few words of explanation are necessary before presenting the tabulation. Under the monothalamous galls were included those types which, so far as could be determined, are generally one-chambered, that is, the gall never is a structure constantly characterized by the confluence of the walls of two or more chambers as in the polythalamous condition. A few species are intermediate and were classified in the direction in which it was believed they leaned the more strongly. A number of galls, such as the erineum (hypertrophied epidermal cells) types, do not fall in either of the above categories and cannot be included in such a classification. In those cases in which sufficient data were available, an attempt was made to study the galls on the basis of Kuster's division of cecidia into kataplasmas and prosoplasmas. By " kataplasmas " KusTER means those indefinite, indeterminate galls whose structure is developed through hyperplasia of embryonic tissue, the end product not becoming in its differentiation, orientation, and form of tissues fundamentally different from the normal plant part. "Prosoplasmas," on the other hand, are highly definite and deter- minate galls whose structure differs fundamentally from the normal plant, the tissues in their form and orientation characters con- stituting an aggregation of new qualities. These two groups intergrade, but the intergrading forms are relatively few in number and were classified according to what was believed to be the predominating condition. In all cases where data were not suffi- cient to pass judgment, the gall was omitted from the census. Another set of figures presented is that based on Kuster's classification of galls into organoid and histoid types. An "organoid" gall is one in which an entire plant organ (leaf, stem, 540 BOTANICAL GAZETTE [june internode, ovulary, etc.) as a unit suffers modification without a fundamental change in its morphology. The "histoid" galls are those more numerous types in which an entire plant organ is not involved, the gall being more or less definitely appendicular. This group includes all of the prosoplasmas and part of the kataplasmas. DATA BASED ON NUMBER OF CHAMBERS Monothalamous galls 4°S Polythalamous galls 134 Non-chambered galls 67 Insufficient data to classify 183 The excessively large number of monothalamous forms is a fact related to the character of oviposition. If the eggs are habitually deposited in an aggregate manner, a polythalamous gall is almost certain to result, although there are striking exceptions to this. The great majority of larvae, however, begin their gall-making activity at sufficient distance apart to develop the common mono- thalamous types of cecidia. KATAPLASMAS AND PROSOPLASMAS Kataplasmas 395 Prosoplasmas 3 22 Insufficient data to classify 73 Viewed from an evolutionary standpoint, the kataplasmas represent the lower levels and the prosoplasmas the higher. That the latter have undergone a considerable expansion indicating relatively rapid progress in recent geologic time is evidenced by the relatively large number of prosoplasmas. ORGANOID AND HISTOID GALLS Organoid 215 Histoid 495 Insufficient data to classify 82 These figures have no special significance, perhaps, other than the indication of differences in the range of the gall stimulus. In the organoid types the stimulus is diffused over relatively large areas, inciting all of the tissues of one organ to hypertrophy and hyperplasia. In the histoid forms the stimulus only affects those tissues in a restricted area about the cecidozoon, these tissues responding in a definite and striking manner. 1918] WELLS—Z00CEC1DIA 541 In addition to the above two tables Kuster has, in his classifica- tion of cecidia, furnished the basis for another table in his analysis of the prosoplasmas. These he divides into four groups: the leaf edge "roll" galls; the diverticulum or outpouching types; the "walled" (umwallungen) forms, whose walls grow up about the superficial larva; and the concentric (mark) cecidia whose larvae inaugurate gall formation from a point within the tissue. In the following list this classification was extended to include so far as possible the kataplasmas also, since a great many of these latter galls can properly be placed under some one of the preceding four groups. The 58 "rosette" and the 28 erineum types cannot be included. NUMBERS OF VARIOUS GALL TYPES Leaf edge "roll" types 32 Concentric types Diverticulum types 0n leaves 145 On stems 184 On other parts 36 Galls unclassifiable in the above cate- Leaf or leaflet fold along mid- vein 19 Pouch types proper 109 gories 86 Walled (umwallungen) types 87 Unclassified through insufficient data 94 The factors entering into the production of these various kinds of galls are many; a full discussion of them cannot be presented here. Attention, however, should be called to the two main groups, namely, those which are related to the plant and those related to the cecidozoon. The diverticulum galls are, with few exceptions, only known from the leaf, particularly the blade, since this organ only is sufficiently free from stereome tissues to make possible the characteristic pouching out on the side opposite the cecidozoon. The walled and concentric types can occur on any part of the plant, the latter constituting a much larger aggregation than any of the other kinds. Oviposition within the plant tissue or a migration inward on the part of the larva is necessary for the production of the concentric type of gall. Even in these cases constituting the highest galls, plant factors can exert a modifying influence. The study of the relative importance of the two groups of factors entering into cecidium morphogenesis in specific cases is one of the most valuable and suggestive in the field of zoocecidology. University of Arkansas Fayetteville, Ark. 542 BOTANICAL GAZETTE [june LITERATURE CITED i. Connold, E. T., British vegetable galls. New York. 1902. 2. Cook, M. T., The insect galls of Indiana. 29th Ann. Rept. Dept. Geol. and Natural Hist. Indiana, pp. 801-867. 1904. 3. Darboux, and Hotjard, C, Catalog systematique des Zoocecidies de l'Europe at du Bassin mediterranee. Paris, igoi. 4. Felt, E. P., American insect galls. Ottawa Nat. 30:37-39. 1916. 5. Haimhoffen, G. R., Beobachtungen iiber die Menge und das Vorkommen der Prlanzengallen und ihre spezielle Verteilung auf die verschiedenen Pflanzengattungen und Arten. Verhandl. Zool.-Bot. Gesell. 8:285. 1858. 6. Houard, C, Les Zoocecidies des Plantes d'Europe et du Bassin de la Meditteranee. 2 vols. Paris. 1909. Vol. 3, Paris. 1913. 7. Jarvis, T. D., A catalog of the gall insects of Ontario. 39th Ann. Rept. Ent. Soc. Ont. 70-98. 1908. 8. Kieffer, J. J., Synopsis des Zoocecidies d'Europe. Ann. Soc. Entom. France. 70:233-384. 1901. 9. Schlechtendal, D. H. R. v., Gallbildungen (Zoocecidien) der deutschen Gefasspflanzen. Zwickau. 1891. 10. Stebbins, F. A., Insect galls of Springfield, Mass., and vicinity. Bull. 2. Springfield Mus. 19 10. 11. Thompson, M. T., An illustrated catalog of American insect galls. Edited by E. P. Felt. Nassau, N. Y. 1915. ^-229 C - 1* • -^ ► .. ° ^ <** A" O *o . t * A. ^"0 ° > * ^ o V f» .•*.. 2 ^ 0° M .0 %^ • • s