The numerous stamens are graduated in length, and
the pollen-grains from the longest and shortest ones did not present any marked
difference in diameter. Therefore these species do not appear to be
heterostyled.)]
Oxalis (Geraniaceae).
(Figure 4.11. Oxalis speciosa (with the petals removed).
Left: Long-styled.
Centre: Mid-styled.
Right: Short-styled.
S, S, S, stigmas. The dotted lines with arrows show which pollen must be carried
to the stigmas for legitimate fertilisation.)
In 1863 Mr. Roland Trimen wrote to me from the Cape of Good Hope that he had
there found species of Oxalis which presented three forms; and of these he
enclosed drawings and dried specimens. Of one species he collected 43 flowers
from distinct plants, and they consisted of 10 long-styled, 12 mid-styled, and
21 short-styled. Of another species he collected 13 flowers, consisting of 3
long-styled, 7 mid-styled, and 3 short-styled. In 1866 Professor Hildebrand
proved by an examination of the specimens in several herbaria that 20 species
are certainly heterostyled and trimorphic, and 51 others almost certainly so.
(4/12. 'Monatsber. der Akad. der Wiss. Berlin' 1866 pages 352, 372. He gives
drawings of the three forms at page 42 of his 'Geschlechter-Vertheilung' etc.
1867.) He also made some interesting observations on living plants belonging to
one form alone; for at that time he did not possess the three forms of any
living species.
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