Tribe Calypsoeae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 132

California to Montana and Wyoming. The flowers are open in both with a brightly
colored perianth in C. mertensiana and a well-developed stipe in C. wisteriana .
Freudenstein ( 1997 ) examined 253 open flowers of C. wisteriana in a group of
freshly cut racemes received by mail. Rotation of the stipe and autogamy had
occurred in only 2.8% of the flowers. However, the data were ambiguous as no
stigmas had received pollinia from other flowers, and only 15% had pollinaria
removed. The floral characters in both species are nevertheless consistent with
insect pollination and outcrossing.
Aplectrum Nuttall
Aplectrum is a monospecific genus found in the eastern United States and Canada
(Pridgeon et al. 2005 ).
Aplectrum hyemale (Muhlenberg ex Willdenow) Nuttall
(Adam and Eve Orchid, Putty-Root)
Habitat and Distribution
A. hyemale , a wintergreen orchid, is often densely aggregated in the rich soils of
mesic to wet-mesic, deciduous forest (Sheviak 1974 ; Case 1987 ). It ranges from
Minnesota, southern Quebec, and Massachusetts to Oklahoma and Georgia with
occasional disjunct populations outside this range (Auclair 1972 ; Magrath 2002 ).
Floral Morphology
A relatively constant number of medium-sized, resupinate flowers are borne in a
loose raceme (Table 6.5 ) (Luer 1975 ). Sepals and lateral petals vary in color from
yellow to green, tinged with magenta or purple-brown (Luer 1975 ; Smith 1993 ). The
sepals are spreading whereas the petals parallel the column (Fig. 6.11a ). The label-
lum is obovate and 3-lobed (Fig. 6.11b ). The central lobe, whitish with purple mark-
ings, is large and orbicular with an undulate margin and three fleshy lamellae on its
lower half (Fig. 6.11a, b ). Small, ovate lateral lobes are present on either side toward
the middle and ascend to flank the column (Fig. 6.11a ) (Luer 1975 ; Smith 1993 ;
Magrath 2002 ). The column is compressed, elongate, 7 mm long, and pale green with
purple spots. As in the preceding members of the Calypsoeae, it bears a terminal,
incumbent anther and one pollinarium comprised of four hard, superposed, yellow
pollinia attached to a viscidium by a short stipe (hamulus). The stigma is distinctly
concave (Magrath 2002 ). The plants bloom after the spring ephemerals, and the flow-
ers last about 4 or 5 days (Hogan 1983 ). Nectar is apparently absent (Hogan 1983 ).