1885. | Botany. 995 
those presented at previous meetings, and came up more nearly 
to the standard demanded by the science of to-day. Below we 
give brief abstracts, which will show the general nature of the 
papers. 
“An observation on the hybridization and cross-breeding of 
plants,” by E. Lewis Sturtevant. This gave in detail the obser- 
vations on crossed beans, maize, barley, peppers, tomatoes, lettuce 
and peas, made at the New York Agricultural Experiment Sta- 
tion. Asa result of.the observations the author concludes that in 
our domesticated vegetable plants cross-fertilization shows its 
effects at once in the reproduction of the form-species and varie- 
ties which are involved in the parentage of the crossed seed, or, 
in other words, the effect is atavism rather than a blending of 
properties. 
“ Germination studies,” by the same author, gave the results of 
making numerous duplicate germinations, showing that different 
percentage-results are obtained as the quantity of seeds used is © 
large or small. The influence of various temperatures was also 
discussed. These two papers will appear in the NATURALIST. 
“ The question of bisexuality in the pond-scums,” by Charles 
E. Bessey. It has been held by some botanists that the pond- 
scums (Zygnemacez) show a distinct bisexuality, one of the fila- 
ments being male, the other female. Certain facts were presented 
which render such a view untenable. In many plants the cells of 
the same filament fertilize one another, as is notably the case in 
the forms which have been described as Rhynchonema. Several 
cases of hybridization were cited in which two filaments, both of 
which bore resting-spores, united with one another and produced 
a hybrid spore. The conclusion was that the pond-scums are 
not bisexual, but rather unisexual, that is, that while sexuality un- 
doubtedly exists, there is as yet no differentiation into the proper 
male and female. Accordingly these plants must take a position 
just above the asexual prototypes, but below the clearly bisexual 
oophytes. : 
“The process of fertilization in Campanula americana,” by 
Charles R. Barnes. This species is strongly proterandrous. The 
pollen is scraped out of the anthers by the hairy style and brushed 
off before the stigmas open, thus securing cross-fertilization. The 
development of the pollen is normal. The stigmas are held to- 
gether till mature by interlocking papilla. The hairs on the 
style become partially introverted, thus freeing the pollen. 
The pollen spore contains two nuclei, the larger of which, the 
vegetative, becomes disorganized shortly after entering the pollen 
tube, while the smaller spindle-shaped generative nucleus persists. 
The embryo-sac is cylindrical, with a gradual enlargement near - 
the micropylar end, where is located the egg-apparatus, and an 
abrupt enlargement at the chalazal end, in which lie the antipodal 
cells. There are usually two sac-nuclei. 
VOL, xIX.—no. x, 65 
