BY ALEX. G. HAMILTON. 759 



Strom's important paper on the subject* (with a copy of which 

 the author most kindly favoured me subsequently). Also that 

 Howard (Illust. N. Quinologia) speaks of "the scrobicules or 

 glands [in Cinchona], as Pavon calls them." 



Mr. J. P. Hill sent me Geddes' " Chapters in Modern Botany," 

 on p. 134 of which Lundstrom's views are mentioned. Mr. C. T. 

 Musson obtained for me the reference to Mr. Cheeseman's paper 

 " On the New Zealand Species of Coprosma,"t and so disposed of 

 any doubt that New Zealand naturalists had failed to notice the 

 structures in question in plants of this genus. 



Dr. Lundstrom was the first naturalist who systematically 

 investigated these structures. The following extracts from the 

 summary of it in the Journ. R. Microscop. Soc. (1888, p. 87) will 

 sufficiently indicate the conclusions at which he arrived in his 

 valuable paper. 



" Domatia. — Dr. A. N. Lundstrom defines as 'domatia' those 

 formations or transformations on plants adapted to the habitation 

 of guests, whether animal or vegetable, which are of service to 

 the host, in contrast to cecidia, where such habitation is injurious 

 to the plant. He describes these domatia in detail on the lime, 

 alder, hazel, and other trees and shrubs, and gives a very long 

 list of species, belonging to a great variety of natural orders, on 

 which the}^ are found. 



"The principal types of shelter are as follows : — ^1) Hair-tufts, 

 e.g., in Tilia europcea; (2) recur^'atures or foldings in vai'ious 

 -parts, e.g., in Querciis robiii- . . . ; (3) grooves without hairs, 

 as in Coffea arabica . . . ; with marginal hairs, e.g., Psycho- 

 tria daphnoides . . . ; with basal hairs,, as in Anacardium 

 occideiitale . . . ; (4) pockets, as in Elceocarpus ohlo)igns 

 ; (5) pouches, e.g. Eugenia australis. These difFei'ent 

 types of domatia are connected by transition forms. The habit 

 of producing domatia in a species may become hereditary without 

 the actual presence of the predisposing cause. Certain orders, 



*Xov. Act. R. Soc. So. Upsala, (.3) xiii. (1887), pp. 1-72 (4 pis.). 

 + Ti-ans. N. S. lust. xix. 1886, p. 221 [18S7]. 



