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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"

7 seeds instead of 77.5; and those from the short-styled 6.5, instead of
18.7 seeds per capsule. The number 6.5 agrees closely with Mr. Scott's result
from the same form similarly fertilised.
From some observations by Dr. Torrey, Hottonia inflata, an inhabitant of the
United States, does not appear to be heterostyled, but is remarkable from
producing cleistogamic flowers, as will be seen in the last chapter of this
volume.
Besides the genera Primula and Hottonia, Androsace (vel Gregoria, vel Aretia)
vitalliana is heterostyled. Mr. Scott fertilised with their own pollen 21
flowers on three short-styled plants in the Edinburgh Botanic Gardens, and not
one yielded a single seed; but eight of them which were fertilised with pollen
from one of the other plants of the same form, set two empty capsules. (1/19.
See also Treviranus in 'Botanische Zeitung' 1863 page 6 on this plant being
dimorphic.) He was able to examine only dried specimens of the long-styled
forms. But the evidence seems sufficient to leave hardly a doubt that Androsace
is heterostyled. Fritz Muller sent me from South Brazil dried flowers of a
Statice which he believed to be heterostyled. In the one form the pistil was
considerably longer and the stamens slightly shorter than the corresponding
organs in the other form. But as in the shorter-styled form the stigmas reached
up to the anthers of the same flower, and as I could not detect in the dried
specimens of the two forms any difference in their stigmas, or in the size of
their pollen-grains, I dare not rank this plant as heterostyled.


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