[183]

Franks Letters

Twigs in water in diffused light open — shut early about 3° open in dark cupboard after 24°

Immersed in sun opened, while leaves closed on plant

Made bell-glass damp as in sun open fully

Plant in pot was daily watered, & 1 in open ground never watered & weather during part of time hot & dry. — Leaves on plant in open shut, whilst those on plant in pot open. —

July 24th 4 cans of w. to plant out of doors, next morning wide open; though for several days before shut

Twig in water open, while leaves on plant in garden shut.

[183v]

263C

Ch VI Concluding Remarks

is adapted is enabled to to act efficiently only on the female element of another set. in the other & is in consequence ill adapted, like the reproductive elements of two distinct species to act on the female element of its own form. We need feel no surprise at the occurrence of such constant constitutional differences as not doubt about the possibility of variations in the reproductive system of a varying plant, for we know that some species vary, so as to be completely self-sterile or completely self-fertile, either in an apparently spontaneous manner or from slightly changed conditions of life. so as to be completely self-sterile or completely self-fertile. Gärtner also has shown *(a) that individual plants of the same species vary in their sexual powers in such a manner that one individual will unite much more readily than another with a distinct species. But what the nature of the inner constitutional differences may be between the sets or forms of the same varying hetero-styled species, or between distinct ordinary species, is quite unknown. Finally it appears It seems therefore probable that the species varied which have become heterostyled at first varied so that two or three sets of individuals were formed which differed in the length of