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GrassBase - The Online World Grass Flora
Descriptions
W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson
© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.
Dactyloctenium giganteum
HABIT Annual; caespitose. Culms erect, or geniculately ascending, or decumbent; (37–)70–160 cm long; without nodal roots, or rooting from lower nodes. Ligule a ciliolate membrane. Leaf-blades 11–45 cm long; 5–12 mm wide. Leaf-blade margins glabrous, or tuberculate-ciliate. Leaf-blade apex acuminate.
INFLORESCENCE Inflorescence composed of racemes.
Racemes (1–)3–9; digitate; ascending; unilateral; 3.5–11 cm long. Rhachis deciduous from axis; flattened; terminating in a barren extension; extension bristle-like. Spikelet packing broadside to rhachis; crowded; regular; 2 -rowed.
Spikelets pectinate; solitary. Fertile spikelets sessile.
FERTILE SPIKELETS Spikelets comprising 2–7 fertile florets; with diminished florets at the apex. Spikelets elliptic; laterally compressed; 4–6.2 mm long; breaking up at maturity; disarticulating above glumes but not between florets.
GLUMES Glumes persistent; dissimilar; shorter than spikelet. Lower glume lanceolate, or elliptic; 1.5–2.2 mm long; 1 length of upper glume; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume oblong; 1.5–2.2 mm long; 0.5–0.6 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein smooth. Upper glume lateral veins absent. Upper glume apex truncate; awned; 1 -awned. Upper glume awn subapical; 3–9 mm long.
FLORETS Fertile florets appressed to rhachilla. Fertile lemma not gibbous; lanceolate in profile; 3–4 mm long; membranous; keeled; 3 -veined. Lemma midvein scaberulous. Lemma lateral veins obscure. Lemma apex acute, or cuspidate; mucronate, or awned; 1 -awned. Principal lemma awn 0.7–2 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels wingless. Apical sterile florets resembling fertile though underdeveloped.
FLOWER Anthers 3; 1.3–2.1 mm long.
FRUIT Caryopsis with free soft pericarp; obovoid; 0.7–1.1 mm long; rugose.
DISTRIBUTION Africa: east tropical, southern tropical, south, and western Indian ocean. Australasia: Australia.
NOTES Eragrostideae. FTEA.
ADDITIONAL CHARACTERS Glume awn (1.5-)1.75–4 length of body.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
