136 BOTANICAL GAZETTE [ AUGUSI 
family Calyceracee.— P. GRAEBNER (Zb2d. 120) has published a revision of 
Linnaea, including A éde/ia under it as a subgenus, the genus thus containing 2 
species, 12 of which are new.—The most recent “Contribution from the 
Gray Herbarium” is by M. L. FERNALD (Proc. Am. Acad. 35: 489-57) 
June 1900). It contains a synopsis of the Mexican and Central American 
species of the great genus Sa/via, 209 species being recognized, 57 
of which are new; a much needed revision of the Mexican and Ce 
American species of Solanum § Tovaria, 10 species being presented, four of 
them new ; and some undescribed Mexican seed-plants, 31 in number, chiefly 
Labiatae and Solanaceze.—J. M. C. 
A NEW THEORY of myrmecophily is proposed by Buscalioni and Huber’ 
Writing from Pard, Brazil, last September, they say that Schimper's attrac 
tive theory, that the symbiosis exists on account of the plant’s need of prolte 
tion against leaf cutting ants, not only fails to account for the facts, but'® 
directly contrary to many. They find myrmecophilous plants restricted © 
regions subject to present or recent inundation, which points to 4 connectifa 
between this condition and the development of myrmecophily. This ae 
tion appears simple: when the low regions were overflowed the ants wert 
compelled to take refuge on the trees and shrubs, and naturally sought 0 
the hollow parts in which to stow away their larvae. The fodder P 
for the police-lke guests is probably to be ascribed to the direct influence 
the ants themselves or of the Aphides or Coccide which seek it. As 
regions remoter from the streams became less subject to overflow the ants 
may have retained their dwellings, although the need had passed, while - 
protection to the plants may have given the latter an advantage Ove! Bol 
petitors. ie 
The authors state certain consequences of their theory, which s0 fat a 
proved true: ae 
1) If a plant genus consisting of some ant-free and some myrmecop “ ’ 
Species has different species in the upland and in the inundated land, a a 
rule the upland forms will be free of ants, and only those in the i ee : 
region will be myrmecophilous. oy 
2) Those myrmecophilous species which occur on dry. land ee 
derived either from those which occur in inundated localities oF they ® A 
found in localities which were periodically overflowed in earlier times: wait : 
The myrmecophilous plants of deeply inundated regions a7 ™ 
trees; those in regions of shallow overflow are shrubs. ; é 
The authors promise the publication shortly of thorough investigation : 
the biology and anatomy of the ant plants.— C. R. B. 
In HIS RESEARCH on rheotropism of roots Juel used a neat 
obtaining a current of water of uniform rate to impinge upon rot 
* Beihefte zum Bot. Centralbl, 9: 85-88. 1900. 
evice for 
