Malaxis unifolia Michx.
Green adder's mouth
The specific epithet unifolia is the Latin for "one-leafed,"
in reference to the single leaf of this species.
Photo courtesy of Mark Larocque
DESCRIPTION: Plant glabrous, 10-20
cm tall, arising from an cluster of slender roots; base of the stem swollen
to form a pseudobulb. Leaf solitary, located above the base of the
stem, but with a sheathing base that reaches base of stem, ovate-elliptical,
3-10 cm long and 2-7 cm wide. Midrib prominent, forming a keel below. Inflorescence
a loose, elongate capitate raceme of green flowers, 20-50 flowered; each
flower subtended by a minute lanceolate bract. Sepals ovate-lanceolate
to linear-oblong, 1-1.5 mm long and about 0.5 mm wide, green. Petals
linear, 1-1.5 mm long and about 0.2 mm wide and colored as the sepals; typically
reflexed back along the ovary. Labellum not resupinate, appearing
hourglass-shaped or cordate with the apex divided, the division of the labellum
forming two teeth with a third, smaller tooth between them; 2-3 mm long
and 1-2 mm wide (at widest point), colored as sepals and petals.
SIMILAR SPECIES: Malaxis unifolia could possibly be confused
with M. monophyllos; however, the
elongate inflorescence of M. monophyllos
is distinctly different from the capitate inflorescence of M. unifolia.
In addition, the three-toothed labellum of M. unifolia is easily
distinguished from the acute labellum of M.
monophyllos. In fruit, these taxa can be separated by the length
of the pedicels: the pedicels are shorter than the ovaries in M.
monophyllos and longer than the ovaries in M. unifolia.
HABITAT: Malaxis unifolia is found in a variety of habitats,
but all tend to be characterized by sandy and/or acidic soils. Typical habitats
in Wisconsin include dry, sandy pine or oak woods or jack-pine barrens.
It has also been occasionally collected in moist swampy woods, typically
growing in Sphagnum hummocks.
FLOWERING DATES: July 1-August 20.
POLLINATION: Unknown, although the small size and color of the flowers
suggest pollination by small flies, such as fungus gnats.
WI DISTRIBUTION: 
U.S. DISTRIBUTION:
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