Mr. Thwaites pointed out several years agot that this plant
exists under two forms, which he designated as forma stylosa et
stamineu ; and the flowers sent to me by him are clearly hetero-
styled. In the long-styled form the pistil is nearly twice as
long, and the stamens half as long as the corresponding organs
in the short-styled form. The stigmas of the long-styled seem
rather smailer than those of the short-styled. All the stamens
in the short-styled flowers are of nearly equal length, whereas
in long-styled they differ in length, being alternately a little
longer and shorter; and this difference in the stamens of the
two forms is probably related, as we shall hereafter see in
the case of the short-styled flowers of Lythrum salicaria, to the
manner in which insects can best transport pollen from the
long-styled flowers to the stigmas of the short-styled. The
pollen-grains from the short-styled flowers, though variable in
size, are to those of the long-styled, as far as I could make out,
as 100 to 83 iu their longer diameter. Sethia obtusifolia ig
heterustyled like S. uweuminatu.
* F. Miiller remarks in his let-
ter to me that the flowers, of which
he carefully examiued many spe-
cimens, are curiously variable
in the number of their parts:
5 svpals and petals, 10 stamens
aud 3 pirtils are the prevailing


numbers; but the sepals and jx tala
often vary from 5 to 7; the sta-
mens from 10 to 14, and the pistils
from 3 to 4.
+ ‘Enumeratio Plantarum Zeye
lanis,’ 1864, p. 54.
Cuapr. IID. ZRGIPHILA ELATA. 123


CRATOXYLON FORMOSUM (HYPERICINEZ).
