Spiranthes casei Catling & Cruise
The specific epithet casei honors Fred Case, author of "Orchids
of the Western Great Lakes Region."
DESCRIPTION: Plant pubescent
with capitate hairs above the leaves, 14-38 cm tall (including inflorescence),
arising from a cluster of fleshy, slender roots. Leaves 2-3(-5),
lowermost ovate-lanceolate and forming a loose basal rosette, 7-10 cm long
and 1-2 cm wide, fugacious (withering at flowering), upper leaves persistent,
linear-lanceolate to oblanceolate, 10-20 cm long and 0.5-1 cm wide, grading
into reduced sheathing bracts below the inflorescence. Inflorescence
a downy, loose spicate raceme of 20-40 cream-colored flowers, 14-38 cm tall,
typically forming a loose single spiral, each flower subtended by an elongate,
ovate-lanceolate bract. Sepals lanceolate, 5-7 mm long and about
2 mm wide, the lateral sepals with margins inrolled, and appressed to the
labellum, dorsal sepal connivent with petals to form a hood over the column,
sepals creamy-white to cream colored. Petals lanceolate to oblanceolate,
5-7 mm long and 1-2 mm wide, closely appressed to the dorsal sepal, tips
of dorsal sepal and petals reflexed slightly, colored as sepals. Labellum
ovate, 5-6.5 mm long and 3.5-5 mm wide, apex bent downwards, creamy-white
to cream colored, base of the labellum with two short, pubescent calli.
SIMILAR SPECIES: Easily confused with other species of Spiranthes,
particularly S. cernua and S.
magnicamporum. The spreading lateral sepals, leafless stem at flowering
and odor of S. magnicamporum separate
it from S. casei, which has appressed lateral sepals, a leafy stem
at anthesis and scentless flowers. Separating S.
cernua from S. casei is more difficult. The closely appressed
lateral sepals of S. casei and its creamy color differ from the more
spreading sepals and white color of S. cernua.
In overall appearance, the flowers of S. cernua
appear larger and more open than those of S. casei. Finally, the
inflorescence of S. casei is nearly always loosely single-ranked,
whereas the inflorescence of S. cernua
is usually multi-ranked and frequently densely so.
HABITAT: Spiranthes casei is usually found in dry, sandy, sterile sites.
Common habitats include the tops of sandstone bluffs, and sandy jack-pine
barrens. There is one collection from a wet ditch in sandy soil.
FLOWERING DATES: August 8-September 26, with a peak of records from
the last week of August.
POLLINATION: Catling (1983b)
collected a halictid bee (Dialictus versans) pollinating Spiranthes
casei in Ontario. It is likely that halictid bees or bumblebees also
pollinate S. casei in Wisconsin.
DISCUSSION: A specimen of Spiranthes casei apparently collected by
Umbach August 23, 1900 at Devil's Lake was initially confused with S.
lucida, because of its wide basal leaves (typical of S. casei,
but S. lucida is also characterized by wide leaves). Fuller
(1933) examined the specimen and decided that it represented a wide-leaved
form of S. cernua, missing the differences that separate this taxon
from S. cernua. Some 40 years later, Catling
& Cruise (1974) described S. casei. This specimen is one
of the earliest collections of this species.
WI DISTRIBUTION: U.S. DISTRIBUTION:
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