366 REV. GEORGE HENSLOW ON THE 
Apium petroselinum. This is also self-fertilizing; for Mr. Darwin records that | 
covered plants apparently were as productive as uncovered. 
PASSIFLORACEH.—Passiflora gracilis. This species, unlike other Passion-flowers, 
is an annual, a feature characteristic of self-fertilizers, and * produces spontaneously 
numerous fruits when insects are excluded, and behaves in this respect very differently 
from most of the other species in the genus, which are extremely sterile unless fertilised 
with pollen from a distinct plant” (‘Cross and Self-Fertilization, p. 171), or even 
species. It is worth noting that this species differs from other members in the young 
internodes having the power of revolving. “It exceeds all the other climbing plants | 
which I have examined in the rapidity of its movements, and all tendril-bearers in 
the sensitiveness of the tendrils ” (* Climbing Plants, p.153). Such would seem hardly 
compatible with Mr. Darwin's idea of self-fertilization being injurious. Mr. Darwin 
also records the fact that “flowers on a completely self-impotent plant of Passiflora 
alata fertilised with pollen from its own self-impotent seedlings were quite fertile” 
(* Cross and Self-Fertilisation,’ p. 330). ! 
CAPRIFOLIACEX.—A. curious difference obtains between Sambucus nigra and S. Ebulus. 
In both the anthers are extrorse, while in the latter species the filaments are extraordi- 
narily thick and corrugated (Tab. XLIV. figs. 18 a, b). They stand erect in the middle of - 
the flower, and completely conceal the stigma and obstruct all entrance of the pollen. 
In order to be fertilized the corolla and stamens fall off, leaving the now viscid stigma 
exposed. As the flowers are in a dense corymb, they must get dusted by wind, or else 
later corollas fall upon them. With S. nigra the stamens spread away from the centre, 
the filaments are slender, and the stigma is fully exposed. They are sweet-scented, 
hence the blossoms “ are visited by several insects, but often fertilize themselves, as the 
stamens and pistil ripen simultaneously ” (* Wild Flowers in Relation to Insects,’ p. 109) 
but since the stamens are extrorse there is a greater probability of the pollen being 
transferred from one flower to another. : 
Symphoricarpus, or Snowberry. This is much visited by wasps and bees when the 
shrub is in an exposed situation, but it seems well adapted for self-fertilization. The 
pistil is mature just before the expansion of the corolla; the papillae are long and 
glutinous. The anthers are large, and arch over the stigma. I could detect no honey 
in the flowers, though there is a sort of inverted cone-like disk at the base of the style. 
Pollen-tubes were abundant in the stigma; but whether the grains had been brought by — 
bees or had fallen from the anthers, which shed their pollen as soon as the flower opens, 
I cannot speak positively. When the flowers happen to be ern there would ve 
less likelihood of self-fertilization taking place. 1 
RunrACEX.—Some species of Galium, e. g. G. verum and o Mollugo, are proteran- 
drous, but G. Aparine and, I have no doubt, G. tricorne also are self-fertilizing. Mr. 
Darwin observed that the former species when protected Fraise quite as many seeds. 
as when unprotected. | 
Asperula Cynanchica. This flower has the stamens situated at a higher level iban 
ihe stigma ; puel it would seem to fulfil the oi once bcn to be ee 
