~ 
374 BOTANICAL GAZETTE [MAY 
exhaustive list of the common weeds, grouping them as follows: those 
which propagate by creeping roots, by creeping stems, or by forming 
“crowns.” A summary is made of a number of experiments upon weeds 
with exceptional powers of vegetative reproduction. One of the most striking 
results was in the case of Evs/enia alba, the climbing milkweed. Ten one- 
inch pieces of the root stock were planted ten inches below the surface, and 
seven of these sprouted. The immediately practical value of the report is 
found in the methods suggested for killing perennial weeds, and in illustrated 
descriptions of the underground parts of forty-eight of the commonest vege- 
table pests.—J. G. COULTER. 
Dr. Doueias H. CAMPBELL,’ in continuing his studies among the lower 
the plerome origin of the sporogenous tissue of the stamen. This departure 
from the ordinary hypodermal origin of this tissue is noteworthy. The usual 
indefiniteness of the tapetum was also observed, one or two layers of wall 
cells and certain sterile sporogenous cells functioning as such. Just what the 
“tapetum proper” is it would be difficult to say. 
The development of the megaspore presented no unusual ¢ 
the meager preparations did not permit a clear statement. Th 
variation in these structures to demand multiplied preparations hele <r 
clusions can be regarded as safe. The antipodal cells are not of the Jeane 
cent type, but organize into vigorous cells. A remarkable = 
condition was the occurrence of a mass of tissue in the micropylar end a 
embryo sac, replacing the egg-apparatus. Just what this signifies itis e 
to say. Of course, we should be pleased to discover some certain me i 
the occurrence of nutritive tissue in the embryo sac of angiosperms a 
fertilization, and especially in the micropylar region, and every such 0 
vation as the above stimulates our expectation. : he primary 
Perhaps the most unexpected result is the peculiar relation of f de a 
root apex to the axis of the embryo. Instead of lying in the wot a cot 
minal cotyledon towards the suspensor, it is directed to one side, almo: ant 
tinuing the axis of the lateral stem apex. The author regards this as ae ke 
origin of the root, and remarks that it is suggestive of the root of Isoe ons 
basal segments of the embryo and the suspensor being possibly the ¢4 
lents of the “ foot’’ of pteridophytes. 
The author again finds that the primary suspensor © 
and that the embryo is derived entirely from the termina 
haracters, but 
ere is enough 
ell does not divide, 
1 cell resulting from 
* Annals of Botany 12: 1-28. 1898. 
