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.

Tristachya rehmannii

HABIT Perennial; caespitose. Butt sheaths villous. Culms erect; 20–90 cm long. Lateral branches lacking. Ligule a fringe of hairs. Leaf-blades 10–20 cm long; 1–3 mm wide.

INFLORESCENCE Inflorescence a panicle; comprising 3–18(–24) fertile spikelets. Peduncle smooth, or antrorsely scabrous above; glabrous, or pilose above.

Panicle open; lanceolate; 5–15 cm long; bearing few spikelets.

Spikelets in threes. Fertile spikelets pedicelled; 3 in the cluster. Pedicels fused to each other; united wholly.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; compressed slightly; 25–33 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 2–3 mm long; pubescent; pungent.

GLUMES Glumes persistent; dissimilar; exceeding apex of florets. Lower glume lanceolate; 0.5–0.75 length of spikelet; chartaceous; dark brown, or purple; without keels; 3 -veined. Lower glume surface glabrous, or setose; hairy on veins; with tubercle-based hairs. Lower glume apex acute. Upper glume lanceolate; 1 length of spikelet; chartaceous; yellow; without keels; 3 -veined. Upper glume apex obtuse.

FLORETS Basal sterile florets male; with palea; separately deciduous. Lemma of lower sterile floret similar to upper glume; lanceolate; 0.9 length of spikelet; chartaceous; 5–7 -veined; acute. Fertile lemma oblong; 6–9 mm long; coriaceous; without keel; 7 -veined. Lemma surface pubescent. Lemma margins involute; interlocking with palea keels. Lemma apex lobed; 2 -fid; awned; 3 -awned. Principal lemma awn from a sinus; geniculate; 60–90 mm long overall; with twisted column; deciduous; abscissing across body of lemma. Lateral lemma awns arising on apex of lobes; deciduous with the principal; 14–20 mm long; shorter than principal. Palea 2 -veined. Palea keels approximate; thickened.

FLOWER Anthers 3. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; hairy at apex.

DISTRIBUTION Africa: west-central tropical, east tropical, southern tropical, and south.

NOTES Arundinelleae. FTEA.

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