Tribe Calypsoeae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 106

Table 6.1 Data on Calypso (Sheviak and Catling 2002 )
Character Calypso bulbosa

Plant height (cm) 4.5-22

Flower number Usually 1

Dorsal sepal (mm) 10-24 × 1.5-5

Lateral sepals (mm) 10-24 × 1.5-5

Lateral petals (mm) 10-24 × 1.5-5

Lip (mm) 13-23 × 4-13

Chromosomes (2 n ) 28

Calypso bulbosa (L.) Oakes (Calypso, Fairy Slipper)

Habitat and Distribution

4WO.ORTH!MERICANVARIETIESOFTHISWINTERGREENORCHIDAREKNOWN6ARIETY ameri-
cana (R. Brown) Luer occurs in wet coniferous forests, mixed forests, and bogs
from Alaska to Newfoundland and south to Arizona, New Mexico, Minnesota,
Michigan, and New Hampshire (Sheviak and Catling 2002 6ARIETY occidentalis
(Holzinger) B. Boivin is found in moist to dry, shady coniferous forests from north-
western British Colombia to California and western Montana.

Floral Morphology

A usually single, slightly pendant to horizontal, resupinate flower is borne termi-
nally on a stalk of varying length (Table 6.1 ) (Luer 1975 ; Sheviak and Catling 2002 ).
Sepals and petals are ascending to erect and loosely twisted (Fig. 6.1a ). Both are
usually colored pink or magenta. The lip is deeply saccate, producing a slipper with
a basal orifice, a rounded heel, and a two-spurred toe or apex (Fig. 6.1a ) (Luer 1975 ;
Sheviak and Catling 2002 ). The margin of the lip is everted and dilated distally to
form a broad, apron-like lamella. In variety a mericana , the lamella is white or
washed with pink and bears a conspicuous cluster of contrasting yellow bristles at
its base. In variety occidentalis , it is a dull white with reddish mottling, and the
basal bristles are sparse, whitish, and inconspicuous (Luer 1975 ; Sheviak and
Catling 2002 ). The inside of the slipper in both is marked by fine streaks and spots
of rich purple leading down into the two horn-like spurs under the lip apex (Kipping
1971 ; Stoutamire 1971 ; Luer 1975 ). Contrary to many reports, Kipping ( 1971 ) did
not say nectar was present in variety occidentalis , and Krell ( 1977 ) and Ackerman
( 1981 STATESPECIlCALLYTHATITISABSENT6ARIETY americana is also nectarless accord-
ing to Mosquin ( 1970 ), Stoutamire ( 1971 ), and Boyden ( 1982 ), and the double nec-
tar spurs in both varieties are deceptive devices.
The column is rose pink, broadly winged, nearly circular, and convex, forming a
petaloid hood over the lip just above the entrance to the flower (Fig. 6.1a, d ) (Mosquin
1970 ; Ackerman 1981 ; Boyden 1982 ). An operculate, subterminal anther is posi-
tioned on the lower surface and contains two pairs of flattened and superposed,