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 costaricensis

HABIT Perennial; caespitose. Culms geniculately ascending; 20–40 cm long; wiry. Leaves cauline; distichous. Ligule a ciliolate membrane; 0.5 mm long. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades spreading; lanceolate; 3.5–4.5 cm long; 4.5–9 mm wide. Leaf-blade surface pilose; densely hairy; hairy abaxially; with tubercle-based hairs. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Inflorescence a panicle; comprising 1 fertile spikelets (and 5–10 male); terminal and axillary. Axillary inflorescences present in upper axils and in lower axils.

Panicle open; lanceolate; 1.5–2 cm long; bearing few spikelets.

Sexes segregated; on unisexual branches; with male below. Spikelets solitary. Fertile spikelets pedicelled. Male spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 8–9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 1 mm long; woolly; truncate.

GLUMES Glumes deciduous; similar; with lower wider than upper; exceeding apex of florets; thinner than fertile lemma. Lower glume elliptic; 8–9 mm long; 1 length of upper glume; membranous; pallid; without keels; 11 -veined. Lower glume apex acuminate. Upper glume elliptic; 8–9 mm long; 1.5 length of adjacent fertile lemma; membranous; pallid; without keels; 9 -veined. Upper glume apex acuminate.

FLORETS Fertile florets female. Fertile lemma elliptic; dorsally compressed; 5.5 mm long; indurate; without keel; 5 -veined. Lemma surface pilose; hairy below. Lemma apex acute. Palea 1 length of lemma; indurate; 6 -veined.

FLOWER Lodicules 3; membranous; truncate. Anthers 3. Stigmas 2; terminally exserted; sparsely hairy.

MALE Male spikelets distinct from female; 1 flowered; lanceolate; 3–3.7 mm long. Male spikelet glumes absent. Male spikelet lemma 3 -veined.

DISTRIBUTION South America: Mesoamericana.

NOTES Olyreae. Pohl.

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