In some species the hypogynium forms a prominent collar, while in others it is an inconspicuous ridge around the point of achene attachment.
Achenes roundly trigonous to terete, globose or ellipsoid; surface smooth, tuberculate (warty), pitted, or lobed, rarely pubescent; hypogynium disk-like, lobed or entire, sometimes absent.
Inflorescence an erect, interrupted spike of several sessile glomerules; hypogynium, a short, cylindrical disk, or absent 5.
Inflorescence of one or more terminal and lateral fascicles, paniculate; hypogynium well-developed.
Hypogynium obscurely trigonous, with a whitish papillose crust, lacking tubercles 4.
Achenes pitted, pubescent with tufts or lines of small hairs; hypogynium 3-lobed, the lobes oblong to lanceolate 1.
Achene tuberculate and papillate; glabrous; hypogynium with 6 globose tubercles in distinct pairs 3.
5) mm long, globose to ovoid, with obtuse, apiculate apex, conspicuously pitted, white or gray, with tufts or lines of minute, yellowish to purplish hairs; hypogynium distinctly 3-lobed, the lobes oblong to lanceolate, apex obtuse to subacute, appressed to achene base.
Achenes 3-4 mm long, ovoid to subglobose, with obtuse, usually apiculate apex, smooth, glossy, white; hypogynium base obtuse trigonous, with 8-9 small, rounded or elongated , granular tubercles.
The surface of the achene was smooth and the hypogynium consisted of eight granular tubercles.
5 mm long, ovoid to globose, with obtuse, apiculate apex, irregularly transversely tuberculate and papillate, sometimes the papillae near the base elongate and spinulose; hypogynium narrow, somewhat trigonous, with 6 finely puberulent globose tubercles in distinct pairs.