dropogon scoparius, Linum sulcatum, Aster azureus, 
Petalostemum purpureum.”” full sun. soil dry cal- 
‘areous loess. Bland Hill Prairie, 38.2 miles N. of 
KKIldred, Greene County. 7 November 1969."" (‘To 
be deposited at ILL.) 
Spiranthes magnicamporum occurs on dry prairies and 
related grasslands from northwestern Indiana onto the 
Great Plains (hence the specific epithet “*magnicampo- 
rum’, a direct translation of ‘‘of the Great Plains’’) 
with disjunct populations on the prairies of western Ohio 
and the black belt of Mississippi and Alabama. It ranges 
from Texas north to at least North Dakota. 
Spiranthes magnicamporum differs from WS. cernua var. 
cernua in several characters. The flowers of well devel- 
oped plants of S. magnicamporum are larger than those 
of var. cernua, the perianth often exceeding 1 cm. in 
length. The lip of S. magnicamporum is uniformly oblong- 
ovate to rhombic-ovate, characteristically without the 
dilated base usually present in var.cernua. In var. cernua, 
the apical portion of the lip is also occasionally dilated, 
thus producing a lip with a median constriction, These 
dilations are nearly always absent in typical S. magni- 
camporum. The central portion of the lip of typical S. 
magnicamporum always supports a prominent thickening 
that is distinct even in boiled herbarium material. ‘This 
is a variable character in WS. cernua and is often absent. 
Crisping of the lip is less marked in S. magnicamporum 
than in var. cernua, and the laceration of the lip is sup- 
pressed, the margin often quite entire or the apical quar- 
ter merely dentate. Lateral sepals are free and widely 
spreading to rarely loosely incurved or often ascending, 
unlike those of var. cernua, which closely parallel the 
petals and join to form a hood. The flowers of S. mag- 
nicamporum are often more nearly cream-colored than 
the white usual in var. cera, and the central thicken- 
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