Biology Reference
In-Depth Information
Fig. 6.8
Corallorhiza maculata.
(
a
) Flower, front view; (
b
) Flower, side view; (
c
) Column, viewed
from below, anther in place; (
d
) Column, viewed from below, anther dehisced; (
e
) Column, side
view showing position of pollinia prior to anther dehiscence; (
f
) Column, side view following
anther dehiscence and rotation of pollinia onto the stigma, scale bars = 1 mm.
an
anther,
au
auricle,
me
mentum,
po
pollinia,
ro
rostellum,
sg
stigma
apomixis. Cleistogamous plants achieved 100% seed set in tests for autogamy and
0% in tests for apomixis. The experimental transfer of pollen from cleistogamous to
chasmogamous plants also resulted in 100% seed set. Freudenstein (
1997
) referred
chasmogamous plants of
C. odontorhiza
to variety
pringlei
and cleistogamous
plants to variety
odontorhiza
. Cleistogamous flowers of
C. bentleyi
are also known
to be autogamous (Freudenstein
1999
).
Catling (
1983
) also found 50-100% self-pollination in individual, unmanipulated
plants of
C. trifida
maintained in insect proof cages in a greenhouse, supporting earlier
reports of autogamy in this species (von Kirchner
1922a, b
). Summerhayes (
1951
)
observed similar levels of self-pollination with seed set occurring naturally in 85-100%
of the flowers. Freudenstein (
1997
) also reported a high level of autogamy in a popu-
lation in central New York. In this study, stipe rotation resulted in autogamy in 50% of
the open flowers examined, no stigmas bore any pollinia that were not attached to the
rostellum, and pollinia were removed from only 6.8% of open flowers.
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