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.

Raddiella potaroensis

HABIT Annual; mat forming. Culms decumbent; weak; 5–20 cm long; rooting from lower nodes. Culm-nodes swollen. Leaf-sheaths longer than adjacent culm internode; glabrous on surface. Ligule an eciliate membrane; 0.2–0.4 mm long. Leaf-blade base asymmetrical; with a brief petiole-like connection to sheath; petiole glabrous. Leaf-blades elliptic; 0.9–1.7 cm long; 3–7 mm wide; membranous. Leaf-blade surface glabrous, or puberulous; sparsely hairy; hairy abaxially. Leaf-blade apex acute.

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Inflorescence comprising only a few spikelets; comprising 1 fertile spikelets (and 1–2 male), or 2–3 fertile spikelets (when all female); axillary; exserted, or embraced at base by subtending leaf. Peduncle 0.5–1 cm long.

Sexes segregated (or all female); with male below. Spikelets solitary. Fertile spikelets pedicelled. Male spikelets pedicelled. Pedicels 1–3 mm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic, or ovate; dorsally compressed; 1.2–2.3 mm long; falling entire. Spikelet callus square; incorporating lowest rhachilla internode with adnate lower glume; 0.2 mm long. Rhachilla internodes elongated between glumes.

GLUMES Glumes similar; reaching apex of florets; thinner than fertile lemma. Lower glume elliptic, or ovate; 1.2–2.3 mm long; 1 length of upper glume; membranous; without keels; 3–5 -veined. Lower glume surface pilose. Lower glume apex acute, or acuminate. Upper glume elliptic, or ovate; 1.2–2.3 mm long; 1 length of adjacent fertile lemma; membranous; without keels; 3–5 -veined. Upper glume surface pilose. Upper glume apex acute, or acuminate.

FLORETS Fertile florets female. Fertile lemma elliptic; 1–1.3 mm long; indurate; pallid; shiny; without keel; 3 -veined. Lemma surface papillose. Lemma margins involute. Lemma apex acute. Palea 1 length of lemma; indurate.

FLOWER Anthers 3; 1.7–2 mm long.

FRUIT Caryopsis with adherent pericarp; obovoid; 0.9 mm long. Embryo 0.25 length of caryopsis. Hilum punctiform.

MALE Male spikelets distinct from female; 1 flowered; separately deciduous; lanceolate; 2.7–4.2 mm long; glabrous. Male spikelet glumes absent. Male spikelet lemma 3 -veined; muticous.

DISTRIBUTION South America: northern South America.

NOTES Olyreae. Zul & Jud 1992.

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