Tribe Neottieae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 71

northwestern Montana, but that the effects were not significant. Also, anthracnose
occasionally destroyed some flowering buds; although the long-term effects are
unknown, very few ramets were infected during the study period. In some areas,
serious degeneration of the habitat has resulted from the invasion of exotic species
and such human activity as hot springs development, stream flow reduction caused
by extensive groundwater pumping, construction of hydroelectric dams, housing
development, recreation, timber harvest, grazing, and expanding agriculture
(Brunton 1986 ; Coleman 2002 ).
Epipactis helleborine (L.) Crantz (Broad-Leaved Helleborine)
Habitat and Distribution
Naturalized in North America since 1879 (Day 1882 ; Correll 1978 ), this orchid is
found on disturbed sites or in cedar swamps, shaded deciduous, or mixed forest and
along wooded streams, frequently on rocky substrates; it often grows as individual
stems among young trees, where few other herbs are present (Light and MacConaill
1991 ; Boesse 2000 ; Brown and Argus 2002 0RIDGEONETAL 2005 ). Many isolated
populations are scattered throughout the USA and southern Canada (Brown and
Argus 2002 ). A more or less continuous distribution is present from New Brunswick
to New Jersey west to Wisconsin. Several extended ranges are also found in
California and the Washington-British Columbia area.
Floral Morphology
A number of small, resupinate flowers are borne in a loose to moderately dense,
often one-sided raceme (Table 3.3 ) (Judd 1972 ; Brown and Argus 2002 ). The sepals
are spreading and greenish with tinges of purple. The petals are pale green to pink,
purple, or yellowish and, along with the dorsal sepal, extend forward over the
column (Brown and Argus 2002 ). The lip is divided by a transverse constriction into
a distal and basal section, but unlike E. gigantea the hinge mechanism is poorly
developed. The basal section (hypochile) is purplish to brownish and lacks papillae;
deeply concave, it secretes and holds nectar (Fig. 3.5a ) (Luer 1975 ). The distal
section (epichile) is triangular, recurved, and white, green, or purplish with a pair
of fleshy calli near the base. A short column (Table 3.3 ) bears lateral processes
(staminodia) (Luer 1975 ) and a dorsal anther containing a pair of sessile, cleft,
mealy pollinia comprised of tetrads (Fig. 3.5b, d ) (Luer 1975 ; Burns-Balogh et al.
1987 ). The three-lobed stigma is wide, positioned below the anther, and separated
from it by a prominent, rounded rostellum (Luer 1975 ). A fragile membrane again
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and Renz 1958 ).