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.

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.

This variety is more specific in habitats than var. pubescens. It is typically found in fens, bogs and moist meadows.

May 25-June 20.

Unknown to me.

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