Prev | Current Page 164 | Next

Darwin, Charles, 1809-1882

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

Possibly this species was once heterostyled, but is
now becoming sub-dioecious; the short-styled plants having been rendered more
feminine in nature. This would account for their ovaries usually containing more
ovules, and for the variable condition of their pollen-grains. Whether the long-
styled plants are now changing their nature, as would appear to be the case from
the variability of their pollen-grains, and are becoming more masculine, I will
not pretend to conjecture; they might remain as hermaphrodites, for the
coexistence of hermaphrodite and female plants of the same species is by no
means a rare event.
Erythroxylum [sp.?] (Erythroxylidae).
(FIGURE 3.8. Erythroxylon [sp.?]
Left: Long-styled form.
Right: Short-styled form.
From a sketch by Fritz Muller, magnified five times.)
Fritz Muller sent me from South Brazil dried flowers of this tree, together with
the drawings (Figure 3.8.), which show the two forms, magnified about five
times, with the petals removed. In the long-styled form the stigmas project
above the anthers, and the styles are nearly twice as long as those of the
short-styled form, in which the stigmas stand beneath the anthers. The stigmas
in many, but not in all the short-styled flowers are larger than those in the
long-styled. The anthers of the short-styled flowers stand on a level with the
stigmas of the other form; but the stamens are longer by only one-fourth or one-
fifth of their own length than those of the long-styled.


Pages:
152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176