372 REV. GEORGE HENSLOW ON THE 
plants; but of the white variety with a pink mouth, “ fifty pods, of which only a very — 
few were empty, in a covered-up plant contained twenty grains weight of seed; so that ` 
this variety seems to be much more self-fertile than the previous one." "This case is | 
already shown in harmony with the fact that loss of colour seems to be often correlated — 
with self-fertilization. Again, as will be noticed further on, the majority of the British | 
species of plants, which are generally diffused over the world, and are for the most part ` 
self-fertilizing, are also white. Mr. Darwin observes that the “ peloric variety” of  - 
this plant is morphologically, but not physiologically, self-sterile, * as humble-bees ` 
cannot crawl into the narrow tubular flowers.” Ido not know whether peloric varieties : 
of other genera, as Linaria and Calceolaria, are thus self-sterile ; if so, it would seem to 4 
be a case where plants varied so as to bring about an injurious result; for in Antirrhinum — 
it appears to have excluded bees, and at the same time has not become self-fertilizing. 
Verbascum is another very interesting genus. V. pheniceum and V. nigrum Mr, 
Darwin regards as ‘‘ quite sterile," that is, without insect aid; on the other hand, | 
y. Thapsus is “ perfectly self-fertile” if insects are excluded. V. Lychnitis is rather ` 
e self-fertile * than the preceding " (p. 89), though Mr. Darwin elsewhere describes it ` 
* quite" and “ highly self-fertile" (p. 369). ** Kolreuter” (as quoted by Darwin, 
: itia &e.' p. 830), “long ago described plants of V. pheniceum which during two years 
were sterile with their own pollen, but were easily fertilised by that of four other species; 
these plants, however, afterwards became more or less self-fertile in a strangely fluc- — 
tuating manner." This case, then, elearly corroborates the general inference that, just as 3 
the different species of a genus may vary from complete sterility to complete self-fertility — 
in their normalstates, so individual species can do the same under temporary changed | 
environments. This genus, therefore, resembles Corydalis in the former peculiarity, and 
Eschscholtzia californica and Papaver vagum in the latter. 
Calceolaria (greenhouse variety) is, according to Mr. Darwin, highly self-fertile. The 
position of the stigma on the erect style, which stands exactly between the two or three — ` 
anthers, or a little below them, on their erect filaments, is obviously favourable to self- ` 
fertilization, though the flowers are much crossed by insects, and it is therefore difficult ` — 
to keep varieties true (Tab. XLIV. fig. 20d). Some species, as C, eAelidonoides, O. pin- — 
nata, and C. glutinosa (Tab. XLIV. figs. 29 a, b, ei, with viscid foliage, have a remarkable — 
modification in the structure of their stamens. They are, in faet, similar to those of —— 
. Salvia, in the Labiatze ; so that these species are probably not readily self-fertilized. They ` 
constitute the section Aposecos (Gen. Pl. p. 930). The fertile anther-cells are concealed 
beneath the hood on the posterior side, the connectives, which are elongated, and with, 
in some cases, barren anther-cells, project outwards. The filaments are, as in Salvia, very 
short. On depressing the exposed anther-cells, the fertile ones swing round p as in 
that genus. 
~- Mimulus luteus. Mr. Darwin has down that this species is | highly self-fertile when 
insects are excluded, though the bright yellow corolla, didynamous stamens, and irritable ` ` 
flap-like stigmas are evidently adaptations for intercrossing. This species is also notice- - : 
able for the tall white-flowered variety raised by Mr. Darwin, which proved so vigorous | 
and self-fertile. * Inthe fifth me the crossed pes were in sisi e to fui 
