Cypripedium calceolus (L.) var. parviflorum
Small yellow lady's-slipper
The specific epithet calceolus is the Latin meaning "little
shoe," in reference to the slipper-like shape of the labellum. The
varietal name parviflorum is the Latin meaning "small flower,"
in reference to the smaller flower of this variety.
Photo courtesy of Bill Alverson
DESCRIPTION: Plant arising from a rhizome with a fascicle
of numerous fibrous roots, 15-40 cm high; several to many stems may arise
from the same rhizome. Leaves 3-5 (-6), ovate, plicate, 6-15 cm long
and 3-8 cm wide; pubescent. Flowers 1 or rarely 2, each subtended
by a ovate to ovate-lanceolate, green foliaceous bract 3-7 cm long by 0.6-3
cm wide. Sepals apparently two (the result of the fusion of the two
lateral sepals behind the labellum), madder-purple or dark reddish-brown;
dorsal sepal ovate, 3-5 cm long and 1.5-3.5 cm wide; lateral sepals united
and similar to dorsal sepal but typically spirally twisted, tip typically
divided. Petals colored as sepals, lanceolate to linear-lanceolate,
2.5-5 cm long and typically less than 0.6 cm wide; petals usually spirally
twisted. Labellum pouch-shaped, inflated, obovate, 1.5-3 cm long,
opening above with inrolled edges; yellow, streaked or spotted inside and
at the opening with madder-purple.
SIMILAR SPECIES: Cypripedium calceolus var. parviflorum
would most likely be confused with C. calceolus
var. pubescens. C. calceolus var. parviflorum is
distinguished primarily by the smaller labellum and darker sepals, which
are never as light-colored as those of C. calceolus var. pubescens.
HABITAT: This variety is more specific in habitats than var. pubescens.
It is typically found in fens, bogs and moist meadows.
FLOWERING DATES: May 25-June 20.
POLLINATION: Unknown to me.
WI DISTRIBUTION: 
U.S. DISTRIBUTION:
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