746 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
insect slip from the glassy surface of the sepals, and it clutches at the 
small curved tongue-shaped lip which hangs between them. The base 
of this lip is balanced on the apex of the foot of the column ; it gives 
way under the weight of the insect, which is thrown violently on to the 
column, striking the disc of the pollinia, which become fixed with great 
precision on the first segment of the abdomen. The insect then flies to 
another flower, and, going through the same process, places the pollinium 
on the stigma of this second flower. The author regards the whole 
group of Bulbophylleas as specially adapted for fertilization by Diptera ; 
the species of Dendrobium , on the other hand, by bees. 
Fertilization of Physianthus albens.* — Mr. A. Harvey describes 
the peculiar structure of this plant, belonging to the Asclepiadese, and 
known in America as the “ cruel plant.” To the cap which covers the 
pistil are attached five pairs of stiff appendages ; the moths, chiefly Noctia 
gamma, which suck the honey from the nectar-glands, get their proboscis 
caught between these appendages, are unable to remove them, and perish 
in large numbers without performing any useful service to the plant. 
Mr. C. Armstrong suggests f that in its native country, Brazil, this 
plant is visited by larger Lepidoptera, or possibly by humming-birds, 
which are strong enough to break away the stiff appendages, carrying 
off the pollinia with them, and thus bringing about cross-fertilization. 
Dissemination of Seeds.J — Prof. F. Delpino calls attention to the 
fact that there are two entirely different kinds of dissemination in the 
vegetable kingdom, one for short, the other for longer distances. It is 
not uncommon for the same species to produce seeds adapted for both 
kinds of dissemination. This is the case with those plants which 
produce underground seed-vessels from cleistogamous flowers, such as 
Lathyrus ampJiicarpus and Linaria Cymbalaria. Again, in many 
Composite the seeds from the ray-flowers are adapted for dissemination 
to shorter, those from the disc-flowers for that to longer distances. 
Germination of Zostera,§ — Herr H. Jensen finds the mode of ger- 
mination of the seeds in Zostera to be very similar to that in Zannichellia 
and Ruppia. The dehiscence of the pericarp takes place in water, and 
is brought about by the swelling of its mucilaginous innermost layer. 
The lower end of the hypocotyl is expanded into a peltate form, and is 
densely covered with root-hairs during germination. On the side facing 
the micropyle it bears a conical projection which is a reduced radicle, 
but has no trace of a root-cap. 
(2) Nutrition and Growth (including- Movements of Fluids). 
Multiplication of Bryophyllum.|| — From experiments made on the 
leaves of Bryophyllum, planted in the soil after subjection to injuries 
of various kinds, Mr. B. W. Barton comes to the conclusion that the 
marginal buds are most nearly of the nature of axillary buds of the least 
preferred kind, comparable to those on branches of the second or third 
order of ordinary plants, and that they offer an example of an 
* Proc. Canadian Inst., xxv. (1890) pp. 226-9 (8 figs.). 
f T. c., pp. 230-1. $ Malpighia, iv. (1890) pp. 10-3. 
§ Bot. Tidsskr., xvii. (1889). See Bot. Centralbl., xliii. (1890) p. 42. 
|1 Johns Hopkins Univ. Circular, ix. (1890) p. 62. 
