Subtribe Spiranthinae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 31

Ames (wide-leaved ladies'-tresses), S. ovalis Lindley var. erostellata Catling (oval
ladies'-tresses), and S. ovalis var. ovalis (oval ladies'-tresses) (Table 2.2 ).
Distribution and Habitat
Most species are variously distributed in the eastern USA from the Atlantic to
Saskatchewan, Nebraska, Kansas, and Texas. The range of S. romanzoffiana , how-
ever, extends across Canada from Newfoundland to the Aleutian Islands and at
elevation to New Mexico, Arizona, Nevada, and California. S. diluvialis is an
amphiploid (2 n = 74) resulting from hybridization of S. romanzoffiana (2 n = 44) and
S. magnicamporum (2 n = 30), probably during the last glacial period (Sheviak 1984 ;
Arft and Ranker 1998 ). A rare riparian species, it is confined to mesic or wet mead-
ows and marshes near permanent drainage systems, springs, or large lakes scattered
from Nebraska and Montana to Nevada and Washington (Sipes et al. 1993 ; Sheviak
and Brown 2002 ; Bjork et al. 2008 ). S. lucida , S. romanzoffiana , and S. laciniata are
also frequently found in wet to mesic sites from calcareous fens and shorelines to
meadows (Luer 1975 ; Catling 1980b ; Sheviak and Brown 2002 ). The remaining
species occur in a wide range of situations, including open forests, grassy meadows,
old fields, and roadside ditches (Luer 1975 ; Sheviak and Brown 2002 ).
Floral Morphology
The lip varies from white, often with a yellowish tinge or a yellowish or greenish
center, to rich saffron yellow with green tints in S. lucida . The column lacks a rostel-
lum and viscidium in S. ovalis var. erostellata (Catling 1983b ).
The flowers of S. diluvialis have a faint, coumarin-like scent while those of S.
romanzoffiana are said to produce a weak and musty-sweet or vanilla-like odor
(Sheviak 1984 ; Larson and Larson 1990 ). Flowers of sexual species bloom for
10-40 days and initiate capsule dehiscence 14 (7-21) days after pollination (Catling
1982 ). Flowers over 30 days old are no longer functional. S. lucida blooms much
earlier than the other sexual species and is further distinguished by a number of
floral features, including the shape of its viscidium, the location of its nectar, and the
orientation of its stigma (see below) (Catling 1983c, 1990 ) .
Compatibility and Breeding System
Catling ( 1982 ) found that there was no expansion of the ovary or development of
seed in caged, unmanipulated flowers of S. lacera var. lacera , S. lucida , S. romanzo-
ffiana , S. vernalis , or populations of S. ochroleuca from Pennsylvania and New York