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calypso, calypso orchid, fairy-slipper, fairy-slipper orchid, Venus' slipper

Habit Plants 4.5–22 cm.

blade elliptic to suborbiculate or ovate, often cordate, 10–65 × 12–52 mm.


floral bracts lance-acuminate, 5–28 mm.


pink, magenta, or rarely white;

sepals and petals erect-spreading, linear-lanceolate to linear-oblong, 10–24 × 1.5–5 mm;

lip 13–23 × 4–13 mm, lamina shorter than to longer than apical horns, basal bristles sparse to extensive, brightly and contrastingly colored to dull and obscure.


erect, ellipsoid to lanceoloid, 2–3 × 1–1.5 cm.


= 28 [var. bulbosa].

Calypso bulbosa

Orchidaceae subfam. epidendroideae

from USDA
North America; Circumpolar; Europe; Asia (China, Japan, Russia)
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Varieties 3 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

1. Bristles of lip yellow, extensive; lamina white or suffused with pink, usually equaling or longer than horns.
var. americana
1. Bristles of lip whitish or color of lamina, sparse; lamina commonly with reddish markings on dull white, usually shorter than horns.
var. occidentalis
Source FNA vol. 26, p. 623. FNA vol. 26.
Parent taxa Orchidaceae > subfam. Epidendroideae > tribe Calypsoeae > Calypso Orchidaceae
Subordinate taxa
C. bulbosa var. americana, C. bulbosa var. occidentalis
Synonyms Cypripedium bulbosum, Cytherea bulbosa
Name authority (Linnaeus) Oakes: in Z. Thompson, Nat. Hist. Vermont 1: 200. (1842) Lindley: Lindley, Coll. Bot., App 1826
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