See 
1905] CURRENT LITERATURE 311 
ardella, Solanum, Pentstemon (3), Castilleia (3), Valeriana (2), Coleosanthus, 
Grindelia (2), Gutierrezia (2), Chrysopsis (4), Solidago (6), Oligoneuron, Chrys- 
othamnus (2), and Aster (5).—J. M. C. 
Lyon’? has stated more in detail his views as to the phylogeny of the cotyle- 
dons of angiosperms. The monophyletic origin of angiosperms is argued with 
considerable fullness; a view which recent anatomical studies have helped to estab- 
lish, and to which there is probably little dissent at present. The cotyledons are 
regarded as primarily haustorial organs, related phylogenetically to the so-called 
foot of bryophytes and pteridophytes; a view which seems to be well taken and 
cogently argued. The monocotyledonous condition is claimed to be the primitive 
one among angiosperms, the dicotyledonous condition being derived from it 
through the “bifurcation” of the originally single cotyledon. This last view is 
probably the only one that will meet serious opposition, since the recent studies 
of the comparative anatomy of the vascular systems of the two groups have con- 
tributed great strength to the view that monocotyledons have been derived from 
dicotyledons. However, this detail does not affect the general claim as to the 
nature of cotyledons. Beginning with the sporophyte of bryophytes, in which 
the body is differentiated into two regions called “sporophore” and “haustrum,” 
the latter is traced through into the angiosperms and shown to include cotyledon, _ 
hypocotyl, and primary root. In fact, the hypocotyl is regarded as a new “haus- 
tral” structure that is differentiated between the root and the sporophore. The 
term “protocorm” is used instead of ‘“proembryo” for the undifferentiated embryo, 
and “metacorm” for the “plant body after the differentiation of its permanent 
members.” The author announces that a paper is in preparation in which he 
“will endeavor to demonstrate the validity of his hypothesis concerning the phy- 
logeny of the cotyledon.” —J. M. C 
with large mobile starch grains. Roots with 1.5™™ removed remain straight, 
having no such new cells. The regeneration of the perceptive complex is not 
always complete before the root becomes geotropic, certain older cells often 
acquiring motile starch grains and perceptive sensitiveness. also ad — 
‘urther evidence from the behavior of inverted root-tips and replies to objections 
based upon the results with glass-capped roots, where thigmotropic curvatures 
(this in the face of NEwcomBE’s results) may enter. Against CzAPEK’s objec- 
tion, that the chemical differences between stimulated and unstimulated roots are 
observed whether the statocysts are present or not, it is suggested that there 
a, 
*° Lyon, HAROLD L., The embrvo of the angiosperms. Amer. Naturalist 39: 
13-35. 1905. 
NEmec, B., Einiges iiber den Geotropismus der Wurzeln. Beiheft 
it : e Bot. 
in 
Centribl. 17:45-60. 1904 
