Aristida vaginata

HABIT Perennial; caespitose. Culms erect; 100 cm long; 2.4 mm diam. Leaf-sheaths tight; wider than blade at the collar; without keel; glabrous on surface. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs. Leaf-blades flat; 1–3 mm wide. Leaf-blade surface ribbed; scabrous; rough adaxially; glabrous; hairless throughout, or except near base. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 30 cm long. Primary panicle branches appressed; 5–8 cm long. Panicle axis scabrous.

Spikelets appressed; solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 11 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; winged; these appendages 0.5 mm long; pubescent; obtuse.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 10 mm long; 0.9 length of upper glume; membranous; 3 -veined. Lower glume surface scabrous. Lower glume apex setaceously attenuate. Upper glume lanceolate; 11 mm long; membranous. Upper glume surface asperulous. Upper glume apex setaceously attenuate.

FLORETS Fertile lemma linear; subterete; 6–7 mm long; coriaceous; without keel; 3 -veined. Lemma surface scaberulous; rough above. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn geniculate; with 20–35 mm long limb; with a straight or slightly twisted column; persistent. Column of lemma awn 2–3 mm long. Lateral lemma awns 20–35 mm long; subequal to principal.

FLOWER Anthers 3.

DISTRIBUTION North America: Mexico.

NOTES Aristideae. Hitchcock 2001.

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