023 millimetres in length. In the short-styled form the anthers
are larger, and the pollen-grains, when distended with water, are to those from
the long-styled form as 100 to 72 in diameter.
Selected capsules from some long-styled plants growing in the Botanic Gardens at
Cambridge, U.S., near where plants of the other form grew, contained on an
average 13 seeds; but these plants must have been subjected to unfavourable
conditions, for some long-styled plants in a state of nature yielded an average
of 21.5 seeds per capsule. Some short-styled plants, which had been planted by
themselves in the Botanic Gardens, where it was not likely that they would have
been visited by insects that had previously visited long-styled plants, produced
capsules, eleven of which were wholly sterile, but one contained 4, and another
8 seeds. So that the short-styled form seems to be very sterile with its own
pollen. Professor Asa Gray informs me that the other North American species of
this genus are likewise heterostyled.
Oldenlandia [sp.?] (Rubiaceae).
Mr. J. Scott sent me from India dried flowers of a heterostyled species of this
genus, which is closely allied to the last. The pistil in the long-styled
flowers is longer by about a quarter of its length, and the stamens shorter in
about the same proportion, than the corresponding organs in the short-styled
flowers.
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