bd 
40 . General Notes. [January, 
_ stigmas ready to receive it by the time the upper flowers are be- 
ginning to shed their pollen. In this inconspicuous class, on the 
other hand, the lower flowers will be in the second or male stage 
when the upper flowers are as yet in the younger or female stage. 
Now it is clear that an insect visiting such flowers, must adhere 
to the habit of the bee, which invariably begins at the lower flower 
on a stalk and goes upwards, taking each flower in regular suc- 
cession. By this means it invariably enters first a female flower 
and there deposits the pollen it brings with it from another plant. 
Were the bee to reverse this order, the whole elaborate arrange- 
ments of many plants for cross-fertilization would be upset, for the 
bee would simply transfer pollen from the upper male flowers and 
deposit it on the lower female ones. This would be fertilization 
by flowers of the same plant, and this Mr. Darwin has shown to 
be little or no better than self-fertilization. In the case of the in- 
conspicuous flowers, where the opposite condition obtains, a bee 
would frustrate fertilization by adhering to its ordinary ascending 
habit. Mr. Wilson’s observations of a wasp visiting these plants 
indicate that the wasp begins at the top flower and proceeds down- 
wards—so that they are adapted specially to such insects, and 
as wasps are generally predatory in their habits, and not entirely 
vegetable feeders, as bees are, it is probable that, like other car- 
nivorous creatures, their perceptions of vision and scent are keen- 
er; hence wasps can probably find these obscure flowers quite as 
easily as a bee can a highly-colored one. The plant, therefore, 
finds that the material can be more economically utilized than in 
the production of a colored corolla just as in the case of self-fer- 
tile cleistogamic flowers. 
Botanica, News.—At the last meeting of the British Associa- 
tion Mr. A7 S. Wilson read some notes on dimorphic plants. 
The plants referred to in this paper were Arythrea centaurium, 
which appears from a microscopic examination of the pollen to 
be a dimorphic plant like the primrose or bog-bean; and Siene 
acaulis, which presents three forms—a male, having stamens only, 
a female, with rudimentary stamens and perfect pistils, and a per- 
fect hermaphrodite form, having both complete. In this respect 
it resembles S. inflata, which, according to Axell, is triceciously 
polygamous, 
Mr. Wilson also remarked on “Some Mechanical Arrangements 
Subserving Cross-Fertilization of Plants by Insects.” This pa- 
per had reference to the three plants, Vinca minor, Pinguicula vul- 
garis, and foxglove—and was a description of*latch-like arrange- 
ments in the latter two, and a knee-shaped bend in the first, which 
when depressed by an insect entering the flowers, cause the pollen 
to be deposited on the insect, and, in the case of Vinca, to 
smear the pollen with viscid matter from the circumference of the 
~ curiously-shaped disc forming the lower part of the stigma. 
