Aristida tuberculosa

HABIT Annual. Butt sheaths villous. Culms erect; 24–50 cm long. Lateral branches ample; arising from lower culm. Leaf-sheaths glabrous on surface; outer margin glabrous, or hairy. Ligule a fringe of hairs. Leaf-blades involute; 10–20 cm long; 1–3 mm wide. Leaf-blade surface ribbed; scabrous; rough adaxially. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; 10–20 cm long. Primary panicle branches ascending; 2 -nate. Panicle branches with prominent pulvini.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 6–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 3–4 mm long; pubescent; pungent.

GLUMES Glumes similar; shorter than spikelet, or reaching apex of florets; thinner than fertile lemma. Lower glume linear; 6–12 mm long; 1 length of upper glume; membranous. Lower glume apex acute; awned; 1 -awned. Lower glume awn 3–6 mm long. Upper glume linear; 6–12 mm long; membranous. Upper glume apex acute; awned; 1 -awned. Upper glume awn 3–6 mm long.

FLORETS Fertile lemma linear; subterete; 11–13 mm long; coriaceous; without keel; 3 -veined. Lemma surface scabrous; rough above. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn 3-branched; spreading, or recurved at base of limb; with 20–40 mm long limb; with twisted column; deciduous; abscissing from top of lemma. Column of lemma awn 10–15 mm long. Lateral lemma awns spreading as much as principal; 30–40 mm long; subequal to principal.

FLOWER Anthers 3.

DISTRIBUTION North America: north-central USA, northeast USA, and southeast USA.

NOTES Aristideae. Gr Indiana 1994.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.