“oa 
982 THE AMERICAN NATURALIST. [Vor. XXXVI. 
results of a considerable series of experiments. In the same num- 
ber of this journal Francis Darwin makes use of germinating Setaria, 
Sorghum, and Vicia faba in experiments on gravitational sensitiveness 
of the root tip. 
A very interesting paper by Ethel Sargent, * Thé Origin of the 
Seed-Leaf in Monocotyledons ” (Wew Phytologist, Vol. I, pp. 107—113, 
Pl. II), gives some of the results of five years’ work on the vascular 
system in monocotyledons. She points out the fact that theoretically 
taxonomic characters drawn from the embryo ate entitled to special 
attention in plants as in animals, but that so far the only important 
strictly embryonic character of acknowledged value is that employed 
in the fundamental division of the apparently well-defined group of 
angiosperms. Concluding that a detailed study of the seedlings of 
one family would yield results of greater value than a general study, 
work for the last four years has been confined to the Liliacez, of 
which seedlings of sixty genera have been collected and preserved, 
but the detailed examination of which is not yet completed. She con- 
siders that there is now no doubt of the systematic value of the indi- 
cations given by the vascular structure of the cotyledon, hypocotyl, 
and primaryroot. At the same time, these indications she considers 
not easy of interpretation, since they are often wholly or in part 
concealed by adaptive characteristics which are the effect of environ- 
ment upon an organism at a time when it is so little differentiated as 
to be extraordinarily plastic. In the hypocotyl she found the effects 
of this influence the least marked, but even here the structure must 
be affected by alternations in that of the cotyledon and root. In 
Anemarrhena she found a type of vascular arrangement from which 
others have clearly been derived, and that this form is truly symmet- 
rical throughout. This type seems to be the starting point of at 
least four central tribes in the Liliacez, and must therefore be a 
form of some antiquity among monocotyledons. A comparison of 
some Ranunculacez, especially Eranthis, Nigella, and Ranunculus 
ficaria, of well-known monocotyledonous affinities, strengthened her 
opinion that the Anemarrhena type is a dicotyledonous one, and to 
conceive of steps by which two separate cotyledons may gradually 
unite, is, she thinks, easier than to conceive of a single cotyledon 
splitting into two similar members, as suggested by Lyon for Nelum- 
bium. In conclusion, she says that there is no evidence of weight 
for the superior antiquity of monocotyledons, and that in this group 
the complete union of two cotyledons may possibly be due to their 
AMI xs as an absorbing g organ. i A. Harris. 

