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.

Rytidosperma sorianoi

HABIT Perennial; caespitose. Culms 10–25 cm long. Leaf-sheaths pilose; with tubercle-based hairs; outer margin hairy. Leaf-sheath oral hairs bearded. Ligule a fringe of hairs; 0.5 mm long. Leaf-blades flat, or conduplicate; 3–6 cm long; 1.5–2 mm wide. Leaf-blade surface pilose, or hirsute; with tubercle-based hairs.

INFLORESCENCE Inflorescence a panicle; comprising 8–15 fertile spikelets.

Panicle contracted; oblong; 1.5–3 cm long; bearing few spikelets. Panicle branches bearded in axils.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scaberulous.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 6–9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; pilose. Floret callus hairs 0.5–1.5 mm long.

GLUMES Glumes persistent; similar; reaching apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 7.5–8 mm long; 1 length of upper glume; membranous; without keels; 3–5 -veined. Lower glume apex acute. Upper glume lanceolate; 7.5–8 mm long; 1.5 length of adjacent fertile lemma; membranous; without keels; 3–5 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; 5–6 mm long; chartaceous; without keel; 9 -veined. Lemma surface pubescent; with 2 transverse rows of hair tufts. Lemma margins ciliate. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 3 -awned. Principal lemma awn from a sinus; geniculate; 6 mm long overall; with a straight or slightly twisted column. Lateral lemma awns arising on apex of lobes; 0.7–1.3 mm long. Palea 3 mm long. Palea surface pilose; hairy on back and on flanks; hairy below. Palea apex acute. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; fleshy; ciliate. Anthers 3; 0.5 mm long.

FRUIT Caryopsis with adherent pericarp; 1.5 mm long. Embryo 0.5 length of caryopsis. Hilum elliptic.

DISTRIBUTION South America: southern South America.

NOTES Arundineae. Fl Pat 1993.

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