Perigynium Comparison with C. cryptolepis
The only two
members of section Ceratocystis found in Saskatchewan are C.
cryptolepis and C. viridula. Note the beak of the perigynium is
much longer in C. cryptolepis.
Answers to key questions in Sedges (Carex) of Saskatchewan, Fascicle 3,
Flora of Saskatchewan by Anna Leighton leading to this species. The
answers are in the order you would normally work through the key.
achenes three-sided, occasionally terete, though their shape may be
concealed by flattened perigynia. NOT [stigmas 2; achenes
or more per culm, terminal and lateral; spike bracts present on lateral
spikes (except in Section Phyllostachyae), lowest bract usually evident,
often conspicuous. NOT [Spikes 1 per culm, terminal; spike bracts
pistillate scales not bract-like or leaf-like but similar in size and
shape to individual perigynia (up to twice as long as perigynia in C.
magellanica ssp. irrigua). NOT [Lower pistillate scales resembling
green, leaf-like bracts much longer and wider than individual perigynia]
glabrous. NOT [Perigynia sparsely to densely pubescent or puberulent (in
C. pedunculata pubescence represented by very short hairs scattered near
tip; in some species of Sect. Acrocystis, perigynia may be glabrous or
virtually hairless, but all members of this group have convexly 3-sided
to terete achenes with tight fitting perigynia and a stipe-like base
about equal to beak in length)]
0.5 mm long and usually visibly bidentate (teeth hyaline in C.
sprengelii, inconspicuous in C. viridula, very short in C. oligosperma).
NOT [Beak absent or less than 0.5 mm long; if more than 0.5 mm long,
then terminating in an orifice without teeth]
jointed at base and deciduous from achene, if present at maturity,
breaks off readily when manipulated. NOT [Style continuous with achene
and persisting at maturity as a long, curved or straight prong]
pistillate spikes sessile or nearly so; base of plant lacking brown
fibers. Section Ceratocystis (C. cryptolepis, C. viridula) NOT
[Lower pistillate spikes with filiform stalks 2-7+ cm long; basal
sheaths shredding to a mass of brown fibers persisting on crown.]
Perigynia 3.5-4.8 mm long; beak about
one-half the length of perigynium, finely but visibly bidentate; most
perigynia spreading to reflexed, a few at top of spike ascending. NOT
1.8-3.5 (3.9) mm long; beak about one-quarter the length of perigynium,
faintly bidentate; most perigynia spreading to ascending, a few at base
of spike reflexed.]