SELF-FERTILIZATION OF PLANTS: 849 
seen in Potentilla Fragariastrum, and often in Stellaria media. After dehiscing, the 
anthers spread away. The order of development of the whorls of R. sceleratus is—calyx, 
pistil, stamens, or corolla. In the preceding species the majority of the stamens mature, 
as stated, before the pistil. R. tuberosus, from Kerguelen’s Island, has only a few 
stamens, is small-flowered, and doubtless self-fertilizing also. 
. The larger-flowered Ranunculi are probably all proterandrous as far as the outer 
series of stamens are concerned ; but as they mature centripetally, the inner may mature 
simultaneously with the carpels, if the outer have then shed their pollen. Myosurus 
minimus has also a reduced number of stamens and is self-fertilizing. Müller has 
described this in detail in * Nature,’ xi. p. 129, from which the following is abridged and 
here inserted, as this plant affords an illustration of an unusual method of self- 
fertilization :— 
Myosurus is as remarkable for the great variability in the size of its flowers, and in the number of its 
parts, as for the enormous growth of the cone of carpels, which affords no other benefit to the plant 
than the self-fertilization of the greater part of the numerous carpels by the small number of anthers 
[about 5], in case it be not aided by insects. The scentless and very inconspicuous flowers are scantily 
visited by small Diptera, not 90 p. c. of the flowers being thus favoured. "The axis of the flower, extending 
gradually, during the blooming-time, into a long cone, brings a great part of the stigmas into contact 
with the lateral pollen-grains of the anthers. "Those ovaries which now are in contact with the anthers 
are soon afterwards elevated above them, while others, previously below the anthers, now reach them, 
Thus a numerous succession of stigmas, by grazing the anthers during the growth of the long cone, 
are self-fertilized with about five or more pollen-grains apiece; besides, also, the lowest stigmas of the 
flowers are fertilized by many pollen-grains falling down from the anthers. Consequently only those 
carpels are never fertilized which are already situated above the anthers before the opening of the flower, 
Müller contrasts this growth of the gynzcium with the elevation of the stamens in 
Myosotis versicolor by the gradual growth of the corolla, which will be found described 
below (p. 375). | 
NyurmzACEX.—Some species are quite self-sterile, but others quite self-fertile. In 
Nymphea alba the innermost stamens are closely adpressed upon the stigma; but I do 
not know whether this species is self-fertilizing or not. According to Delpino, it is 
fertilized by bees *. ; 
.. Paraveracex.—Species of Poppy, Glaucium luteum and others, are by no means self- 
sterile; but Corydalis is remarkable for having some species (e. g. C. cava and C. solida) 
self-sterile, others (e. g. C. intermedia) self-fertile, but evidently adapted for insect- 
- fertilization by the remarkable structure of the corolla. From the latter one infers that 
the small-flowering Fumitory is a degradation or reversion to self-fertilization from an 
intererossing condition. The stamens and pistil of Fumaria are completely inclosed 
Within the petals. 'The stigmas are two in number, ‘and project laterally like blunt 
horns, and are enveloped by the three anthers of each group respectively, which thus 
form, as it were, a three-sided box. The pollen-tubes may be seen entering the stigma | 
in great profusion, the anthers being still in situ. (Tab. XLIV. figs. 3 a, b, c.) The 
. A curious observation was made by one of my pupils, that the stamens can be made to spread out if sir be — 
foiosd tap the peduncle, by Mowing at the cnt end, "on decre 
_ SECOND SERIES.—BOTANY, VOL. I. : 299 
