Platanthera clavellata (Michaux) Luer
Club-spur orchid, small green wood orchid
The specific epithet clavellata is the Latin meaning "club-shaped,"
in reference to the clubbed (clavate!) spur of this species.
glabrous, arising from a cluster of fleshy, thickened roots, 10-33 cm tall.
Leaf 1, oblanceolate to obovate, attached just below the middle of
the stem (although sometimes appearing basal), 6.5-18 cm long and 1.4-5
cm wide, ascending, stem with 1-2 reduced to linear-lanceolate bracts above
the leaf. Inflorescence a loose raceme, 5-15 flowered, the flowers
only incompletely resupinate and thus appearing "askew"; flowers
yellowish-green to green to whitish-green, each flower subtended by a small,
lance-linear, acuminate bract. Sepals ovate, concave, 2-5 mm long
and 1.5-3 mm wide, colored as flowers; dorsal sepal connivent with petals
over the column, lateral sepals slightly spreading. Petals similar
to sepals, connivent with dorsal sepal over the column, colored as flowers.
Labellum oblong to quadrate with the apex shallowly three-lobed,
3-6 mm long and 1-3 mm wide, colored as flowers, base of labellum with a
strongly clubbed (occasionally appearing scrotiform at the tip) nectar spur
projecting behind, about 10 mm long.
SIMILAR SPECIES: Platanthera clavellata could perhaps be confused
with P.obtusata, as both species are
found in swampy or boggy areas and have only one leaf. The two are easily
separated by the shape of the labellum: the labellum is narrow-lanceolate
and acute in P.obtusata, but is oblong
and tridentate in P. clavellata.
HABITAT: Typically found in sphagnous, boggy areas, such as the margin
of sandy lakes, sphagnous swales or meadows, or Sphagnum bogs.
FLOWERING DATES: July 10-August 5.
POLLINATION: Platanthera clavellata is self-pollinating, with
the pollen germinating in the clinandria and growing down into the stigma
(Catling 1983a). This was actually
first described by Asa Gray. Despite this, insects must at least occasionally
visit the plants, as Fred Case has collected a hybrid between P. clavellata
and P. blephariglottis, which he has named P. X vossii
Case (Case 1983).
WI DISTRIBUTION: U.S. DISTRIBUTION:
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