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.

Arberella venezuelae

HABIT Perennial; caespitose. Culms erect, or geniculately ascending; 40–60 cm long. Culm-internodes hollow; distally glabrous, or pubescent. Culm-nodes pubescent. Lateral branches lacking. Leaves cauline; 5–7 per branch. Leaf-sheaths striately veined; glabrous on surface, or hispid; outer margin hairy. Ligule a ciliolate membrane; 0.5 mm long. Leaf-blade base cuneate; asymmetrical; with a brief petiole-like connection to sheath; petiole 0.2 cm long; petiole pubescent. Leaf-blades lanceolate, or ovate; 8–10.5 cm long; 25–35 mm wide. Leaf-blade venation with 6–10 secondary veins. Leaf-blade surface glabrous, or puberulous; hairy abaxially. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Inflorescence a panicle; comprising 1 fertile spikelets (and 3–5 male); terminal and axillary; embraced at base by subtending leaf; with 3–6 peduncles per sheath.

Panicle contracted; linear; 1–2 cm long; bearing few spikelets. Primary panicle branches indistinct the panicle almost racemose.

Sexes segregated; on unisexual branches; with male below. Spikelets solitary. Fertile spikelets pedicelled. Male spikelets pedicelled. Pedicels clavate (female), or filiform (male).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 9–12.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.4–0.7 mm long; truncate.

GLUMES Glumes deciduous; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 9–12.5 mm long; 1.1 length of upper glume; chartaceous; pallid; without keels; 7–9 -veined. Lower glume apex attenuate; awned; 1 -awned. Lower glume awn 1–3 mm long. Upper glume lanceolate; 8–10 mm long; 1.3–1.5 length of adjacent fertile lemma; chartaceous; pallid; without keels; 5–7 -veined. Upper glume apex acuminate.

FLORETS Fertile florets female. Fertile lemma elliptic; dorsally compressed; 6–6.7 mm long; 2.3–2.5 mm wide; indurate; pallid; shiny; without keel. Lemma surface pubescent; hairy above and at base. Lemma margins pubescent. Lemma apex acute. Palea indurate. Palea surface glabrous, or puberulous; hairy above.

FLOWER Lodicules 3; 0.3 mm long; membranous. Anthers 3; 2–2.5 mm long. Stigmas 2.

MALE Male spikelets distinct from female; 1 flowered; linear, or lanceolate; 4–5 mm long. Male spikelet glumes absent. Male spikelet lemma 3 -veined.

DISTRIBUTION South America: northern South America.

NOTES Olyreae. Judzeiwicz 1998.

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