Page:Darwinism by Alfred Wallace 1889.djvu/101

From Wikisource
Jump to navigation Jump to search
This page has been validated.
III
VARIABILITY OF SPECIES IN A STATE OF NATURE
79

in one locality flowers varying from 7/8 inch to 1 3/4 inch in diameter; the bracts varying from 1 1/2 inch to 4 inches across; and the petaloid sepals either broad or narrow, and varying in number from five to ten. Though generally pure white on their upper surface, some specimens are a full pink, while others have a decided bluish tinge.

Mr. Darwin states that he carefully examined a large number of plants of Geranium phæum and G. pyrenaicum (not perhaps truly British but frequently found wild), which had escaped from cultivation, and had spread by seed in an open plantation; and he declares that "the seedlings varied in almost every single character, both in their flowers and foliage, to a degree which I have never seen exceeded; yet they could not have been exposed to any great change of their conditions."[1]

The following examples of variation in important parts of plants were collected by Mr. Darwin and have been copied from his unpublished MSS.:—

"De Candolle (Mem. Soc. Phys. de Genève, tom. ii. part ii. p. 217) states that Papaver bracteatum and P. orientale present indifferently two sepals and four petals, or three sepals and six petals, which is sufficiently rare with other species of the genus."

"In the Primulaceæ and in the great class to which this family belongs the unilocular ovarium is free, but M. Dubury (Mem. Soc. Phys. de Genève, tom. ii. p. 406) has often found individuals in Cyclamen hederæfolium, in which the base of the ovary was connected for a third part of its length with the inferior part of the calyx."

"M. Aug. St. Hilaire (Sur la Gynobase, Mem. des Mus. d'Hist. Nat., tom. x. p. 134), speaking of some bushes of the Gomphia oleæfolia, which he at first thought formed a quite distinct species, says: 'Voilà donc dans un même individu des loges et un style qui se rattachent tantôt a un axe vertical, et tantôt a un gynobase; donc celui-ci n'est qu'un axe veritable; mais cet axe est deprimé au lieu d'être vertical." He adds (p. 151), 'Does not all this indicate that nature has tried, in a manner, in the family of Rutaceæ to produce from a single multilocular ovary, one-styled and symmetrical, several unilocular ovaries, each with its own style.' And he

  1. Animals and Plants under Domestication, vol. ii. p. 258.