Biology Reference
In-Depth Information
Fig. 2.4
Spiranthes vernalis
showing the position of column in newly opened flowers (
a
) and
2-4-day-old flowers (
b
), scale bar = 5 mm.
an
anther,
cl
callus,
po
pollinia,
ro
rostellum,
sg
stigma,
vs
viscidium
S. odorata
is semiaquatic to aquatic, occurring in cypress and hardwood swamps,
marshes, and prairies (Sheviak and Brown
2002
). According to Luer (
1975
), two
forms occur. One prefers heavily shaded, wet woods and rich, acid humus, the other,
full sun in alkaline marshes and wet prairies. It is distributed along the Atlantic and
Gulf Coasts from New Jersey to Texas with disjunct populations in Kentucky and
Tennessee (Catling
1982
; Sheviak and Brown
2002
).
S. casei
var.
casei
grows on mesic to dry, open sites in periodically disturbed,
coarse, sandy soils, frequently on barren ridge tops (Catling and Cruise
1974
). It is
most common from Nova Scotia and northern New England through northern
Pennsylvania, southern Quebec, and southern Ontario to Wisconsin (Catling
1990
;
Sheviak and Brown
2002
).
S. casei
var.
novaescotiae
is found on acidic soils on
barrens and dry roadsides in southern Nova Scotia (Catling
1981
).
Floral Morphology
The lip is white or ivory colored and may have a darker or yellow center. Flowers of
S. ochroleuca
are variously reported to be strongly fragrant (Sheviak
1973
) or to
have a very weak and musty odor (Catling and Brown
1983
) while those of
S. odo-
rata
are said to have a scent similar to that of coumarin, vanilla, or jasmine (Luer
1975
). Flowers of
S. cernua
are either odorless or emit a faint scent resembling that
of fresh
Cypripedium
roots (Sheviak
1973
; Catling and Brown
1983
).
S. magni-
camporum
, on the other hand, has flowers that produce a strong, sweet, and cou-
marin-like fragrance, distinct from that of
S. cernua.
Flowers of agamospermous
taxa bloom for 3-10 days and initiate capsule dehiscence within 2 weeks of bloom-
ing (Catling
1982
).
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