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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.
Rhytachne gonzalezii
HABIT Annual. Culms 20–65 cm long. Culm-internodes distally glabrous. Culm-nodes black. Lateral branches ample. Leaf-sheaths without keel; striately veined; glabrous on surface. Leaf-sheath auricles erect; 0.5–1.5 mm long. Ligule a ciliolate membrane; 0.5–1.1 mm long. Leaf-blades filiform, or linear; involute; 5–30 cm long; 1–4 mm wide. Leaf-blade surface scaberulous; rough adaxially.
INFLORESCENCE Inflorescence composed of racemes. Peduncle glabrous.
Racemes 1; single; smoothly terete; 3–8 cm long; 0.8–1.3 mm wide. Rhachis fragile at the nodes; semiterete; glabrous on surface; glabrous on margins. Rhachis internodes cuneate; 2.7–4.9 mm long. Rhachis internode tip transverse; crateriform; with simple rim.
Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; foliaceous; curved; 2.8–5.2 mm long; glabrous.
STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 3–4.9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; with central peg; attached transversely.
GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; without keels; 4–7 -veined. Lower glume surface muricate; rough generally, or on flanks. Lower glume apex dentate; 2 -fid; muticous, or mucronate, or awned; 1 -awned. Lower glume awn 0–1.9 mm long. Upper glume oblong; membranous; 3 -veined. Upper glume awned; 1 -awned. Upper glume awn 5–16 mm long.
FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret lanceolate; 2.3–3.1 mm long; hyaline; acute. Palea of lower sterile floret 1.2–2.1 mm long. Fertile lemma oblong; 1.8–3.1 mm long; hyaline; without keel. Lemma apex acute. Palea 0.9–1.6 mm long; hyaline.
FLOWER Anthers 3; 0.6–1.2 mm long. Stigmas 2.
FRUIT Caryopsis with adherent pericarp; oblong; isodiametric; 2–2.3 mm long. Embryo 0.5 length of caryopsis. Hilum punctiform.
DISTRIBUTION South America: northern South America and Brazil.
NOTES Andropogoneae. Davidse 1996.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
