Aristida vexativa

HABIT Perennial; caespitose. Culms erect; 15–30 cm long; 0.5 mm diam. Lateral branches lacking. Leaf-sheaths tight; striately veined; glabrous on surface. Leaf-sheath oral hairs pubescent, or ciliate. Ligule a fringe of hairs. Leaf-blades flexuous; conduplicate; 1 mm wide; glaucous. Leaf-blade surface scaberulous; rough adaxially, or on both sides. Leaf-blade margins unthickened. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; interrupted; 15 cm long. Primary panicle branches appressed; 2 -nate; 2–4 cm long. Panicle axis smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scaberulous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 19–20 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; pubescent.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume linear; 9–10 mm long; 0.5 length of upper glume; membranous; 1 -veined. Lower glume primary vein ciliolate. Lower glume lateral veins absent. Lower glume apex awned; 1 -awned. Upper glume linear; 19–20 mm long; 2 length of adjacent fertile lemma; membranous; 1–3 -veined. Upper glume primary vein smooth. Upper glume lateral veins absent, or obscure. Upper glume apex acuminate; awned; 1 -awned.

FLORETS Fertile lemma linear; subterete; 8–11 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 with 70 mm long limb. Lateral lemma awns 70 mm long; subequal to principal. Palea hyaline; 0 -veined.

FLOWER Lodicules 2. Anthers 3.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: southern South America.

NOTES Aristideae. Henrard 1997.

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