Prev | Current Page 180 | Next

Darwin, Charles, 1809-1882

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

Fritz Muller sent me a second, small-sized species, which is
likewise heterostyled.
Coccocypselum [sp.?] (Rubiaceae).
Fritz Muller also sent me dried flowers of this plant from St. Catharina, in
Brazil. The exserted stigma of the long-styled form stands a little above the
level of the exserted anthers of the short-styled form; and the enclosed stigma
of the latter also stands a little above the level of the enclosed anthers in
the long-styled form. The pistil of the long-styled is about twice as long as
that of the short-styled, with its two stigmas considerably longer, more
divergent, and more curled. Fritz Muller informs me that he could detect no
difference in the size of the pollen-grains in the two forms. Nevertheless,
there can be no doubt that this plant is heterostyled.
Lipostoma [sp.?] (Rubiaceae).
Dried flowers of this plant, which grows in small wet ditches in St. Catharina,
in Brazil, were likewise sent me by Fritz Muller. In the long-styled form the
exserted stigma stands rather above the level of the exserted anthers of the
other form; whilst in the short-styled form it stands on a level with the
anthers of the other form. So that the want of strict correspondence in height
between the stigmas and anthers in the two forms is reversed, compared with what
occurs in Hedyotis. The long-styled pistil is to that of the short-styled as 100
to 36 in length; and its divergent stigmas are longer by fully one-third of
their own length than those of the short-styled form.


Pages:
168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192