ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 87 



mycorhiza was found in all the localities examined, whether moory or 

 heathy ; and on the following species : — Vaccinium uliginosum, Oxycoccus, 

 Myriillus, and Vitis-Idasa, Andromeda polifolia, Ledum palustre, and 

 Calluna vulgaris, as well as on cultivated specimens of Vaccinium macro* 

 carpum, Azalea indica, and Rhododendron ponticum, and on Empetrum 

 nigrum. 



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 they are found. 



The principal types of shelter are as follows : — (1) Hair-tufts, e. g. 

 in Tilia europsea ; (2) recurvatures or foldings in various parts, e. g. in 

 'Quercus rob ur, Ilex, Schinus, Ceanothus africanus ; (3) grooves without 

 hairs, as in Coffea arabica, Coprosma baueriana ; with marginal hairs, 

 e. g. in Psychotria daphnoides, Rudgea lanceolata, Faramea, Rhamnus 

 glandulosa, Coprosma Billiardieri ; with basal hairs, as in Ancecardium 

 occidentale ; (4) pockets, as in Elseocarpus oblongus, E. dentatus, Psy- 

 chotria, Lonicera alpigena ; (5) pouches, e. g. Eugenia australis. These 

 different 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, e. g. Eubiacea3 

 (famous also for ant-domatia), show a marked predisposition to acaro- 

 domatia. Many groups seem entirely without them, e. g. Monocotyledons 

 and Gymnosperms, and all herbs. They are most abundant and best 

 developed in tropical (and temperate) zones. 



In the second chapter the author discusses in detail the various 

 interpretations which may be put upon domatia. (1) They may be 

 pathological, like galls ; (2) they may be for catching insects ; (3) they 

 may have only an indirect connection with their tenants ; (4) they may 

 be of use to the plant as the dwellings of commensals. He adopts the 

 last interpretation. He draws an interesting parallel, however, between 

 galls and domatia, and is inclined to suppose that the domatia were first 

 directly caused by the insects, but have gradually become inherent 

 transmitted characteristics. The author gives a clear table, distinguish- 

 ing the cecidia or galls due to " antagonistic symbiosis," either plant or 

 animal (phyto- and zoo-cecidia), and domatia due to " mutual symbiosis," 

 either plant or animal (phyto- and zoo-domatia). Those due to plants 

 are again subdivided into myco- and phyco-cecidia or -domatia. 



Myrmecophilous Plants.t— Herr A. N. Lundstrom observes that 

 several species of Melampyrum are provided with dotdike nectariferous 

 trichomes on their leaves and bracts. These attract large numbers 

 of ants, which he believes arc of service to the plant in the following 

 way. The seeds of these species bear an extraordinary resemblance to 

 the larvas of ants, even to the excrement-sac ; and being mistaken for 

 larva; by the ants, are carried by them to their nests, where they 

 germinate. 



Herr Lundstrom names also a number of myrmecophilous plants 



* Nov. Act. R. Soc. Scient. Upsala, xiii.' (1S87) pp. 1-72 (4 pis.). See this 

 Journal, 1887, p. 273. f Nov. Act. E. Soc. Scient. Upsala, xiii. (1887) pp. 77-88. 



