GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Aristida guayllabambensis

HABIT Perennial; caespitose; clumped densely. Basal innovations intravaginal. Culms erect; 40–60 cm long; 0.5 mm diam. Culm-internodes striate; scaberulous; distally glabrous. Leaf-sheaths subequal to internodes; striately veined; glabrous on surface. Leaf-sheath oral hairs lacking, or ciliate; 1–2 mm long. Ligule a fringe of hairs; 0.2–0.4 mm long. Leaf-blades erect; convolute; 10–20 cm long; 2–2.5 mm wide. Leaf-blade surface ribbed; grooved adaxially; scaberulous; rough adaxially. Leaf-blade margins scabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle; bracteate at branch bases.

Panicle open; linear; 10–30 cm long; 1–2 cm wide; contracted about primary branches. Primary panicle branches appressed; 1 -nate; bearing spikelets almost to the base.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 7–9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.7 mm long; pubescent; acute. Floret callus hairs 0.3–0.7 mm long.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 7–9 mm long; 1 length of upper glume; membranous; purple; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acute to attenuate. Upper glume lanceolate; 7–9 mm long; 1.4–1.8 length of adjacent fertile lemma; membranous; purple; 1-keeled; 1 -veined. Upper glume primary vein scabrous. Upper glume lateral veins absent. Upper glume apex acute to attenuate.

FLORETS Fertile lemma linear; subterete; 5 mm long; 0.3–0.7 mm wide; coriaceous; without keel; 3 -veined. Lemma surface asperulous. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn with 10 mm long limb. Lateral lemma awns 6–10 mm long; subequal to principal, or shorter than principal. Palea oblanceolate; 0.5 mm long; 2 -veined.

FLOWER Lodicules 2; 0.6 mm long. Anthers 3; 2–2.5 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION South America: western South America.

NOTES Aristideae. Laegaard 2001.

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