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 thollonii

HABIT Perennial; caespitose. Butt sheaths pubescent. Culms erect; 30–150 cm long. Ligule a fringe of hairs. Leaf-blades flat, or involute; 5–30 cm long; 2–4 mm wide. Leaf-blade margins entire.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; bilateral; 4–20 cm long; bearing few fertile spikelets; bearing 3–24 fertile spikelets on each. Rhachis angular.

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

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; compressed slightly; 22–37 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 4 mm long; bearded; with longer hairs above; pungent. Floret callus hairs 0.2 length of lemma.

GLUMES Glumes persistent; shorter than spikelet. Lower glume lanceolate; 14–18 mm long; 0.6–0.7 length of spikelet; coriaceous; without keels; 3 -veined. Lower glume surface setose; hairy on veins; with tubercle-based hairs. Lower glume apex acuminate to setaceously attenuate. Upper glume lanceolate; 20–35 mm long; 1 length of spikelet; chartaceous; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea; separately deciduous. Lemma of lower sterile floret similar to upper glume; lanceolate; 22–37 mm long; chartaceous; 5–7 -veined; acuminate. Fertile lemma elliptic; 10–12 mm long; coriaceous; without keel; 7 -veined. Lemma margins involute; interlocking with palea keels. Lemma apex lobed; 2 -fid; incised 0.2 of lemma length; acute; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; subterete below; 50–160 mm long overall; with twisted column; deciduous; abscissing from top of lemma. Palea coriaceous; 2 -veined. Palea keels approximate. Palea surface scaberulous.

FLOWER Anthers 3; 5 mm long. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; linear; hairy at apex. Hilum linear.

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

NOTES Arundinelleae. FTEA.

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