Hyparrhenia dregeana (Nees) Stapf ex Stent

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Gramineae, T. A. Cope. Flora Zambesiaca 10:4. 2002

Morphology General Habit

Robust, densely caespitose perennial; culms up to 200 cm high (or more) and up to 4 mm in diameter at the base, simple or scantily branched.

Morphology Leaves

Basal leaf sheaths silky pubescent below, otherwise all sheaths glabrous; leaf laminas up to 60 cm × 3–8 mm, flat or inrolled and narrower, glabrous, usually stiff and glaucous with scaberulous nerves and harsh to the touch, sometimes soft and green.

Morphology Reproductive morphology Inflorescences

False panicle 20–50 cm long, narrow, fairly dense; spatheoles 2.5–5 cm long, narrowly lanceolate, glabrous or thinly hirsute (rarely the whole panicle copiously villous), becoming reddish-brown; peduncles 1.5–5 cm long, from half as long as to rather longer than the spatheole, pilose above with yellowish hairs; racemes 2–3 cm long, 10–25-awned per pair, usually exserted terminally, tardily deflexed; raceme-bases subequal, the superior 1–1.5 mm long, flattened, stiffly barbate, the apex with a scarious rim and usually produced into a definite oblong appendage up to 0.5 mm long.

Homogamous

Homogamous spikelets 5–7 mm long, a single pair at the base of the inferior raceme only, villous or rarely glabrous.

Morphology Reproductive morphology Inflorescences Spikelets

Sessile spikelets 4–5 mm long; callus c. 1 mm long, cuneate, subacute to narrowly obtuse at the apex; inferior glume oblong-lanceolate, yellowish-green to light brown or purple, densely villous to hispidulous, rarely glabrous; awn (1)8–20(28) mm long, the column pubescent with tawny hairs. Homogamous spikelets 5–7 mm long, a single pair at the base of the inferior raceme only, villous or rarely glabrous. Pedicelled spikelets 5–6 mm long, similar to the sessile spikelets in indumentum and colouring, muticous or with a short awn-point up to 1.5 mm long at the apex; callus scarcely developed; pedicel-tooth obscure.

Sessile

Sessile spikelets 4–5 mm long; callus c. 1 mm long, cuneate, subacute to narrowly obtuse at the apex; inferior glume oblong-lanceolate, yellowish-green to light brown or purple, densely villous to hispidulous, rarely glabrous; awn (1)8–20(28) mm long, the column pubescent with tawny hairs.

Pedicelled

Pedicelled spikelets 5–6 mm long, similar to the sessile spikelets in indumentum and colouring, muticous or with a short awn-point up to 1.5 mm long at the apex; callus scarcely developed; pedicel-tooth obscure.

Morphology General Habit

Perennial; caespitose. Butt sheaths pubescent. Culms erect; robust; 150-200 cm long; 2-4 mm diam. Leaves cauline. Ligule an eciliate membrane; 2-4 mm long. Leaf-blades 30-60 cm long; 3-8 mm wide; stiff; glaucous. Leaf-blade surface scaberulous; glabrous.

Morphology Reproductive morphology Inflorescences

Synflorescence compound; paniculate; 20-50 cm long; dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted, or embraced at base by subtending leaf. Spatheole lanceolate; 2.5-5 cm long; membranous; brown, or red; glabrous, or hirsute. Peduncle 1.5-5 cm long; pilose above. Racemes 2; paired; deflexed; 2-3 cm long; bearing 5-13 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs white. Rhachis internodes linear; 1.5-2 mm long. Rhachis internode tip oblique; flat. Raceme-bases flattened; subequal; 1-1.5 mm long; stiffly setose; scariously rimmed, or extended into an oblong appendage; with 0-0.5 mm long appendage. Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; flattened; ciliate; tip oblique.

Morphology Reproductive morphology Inflorescences Spikelets

Basal sterile spikelets well-developed; on lower raceme 2 in number; 0 in upper raceme; lanceolate; 5-7 mm long; larger than fertile. Basal sterile spikelet glumes glabrous, or villous; ciliate on margins; lower glume muticous. Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 5-6 mm long; longer than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; glabrous, or pubescent, or villous; acute; muticous, or mucronate, or awned; one glume awned; with 0.5-1.5 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1 mm long; pubescent; base obtuse, or acute; attached obliquely.

Sterile

Basal sterile spikelets well-developed; on lower raceme 2 in number; 0 in upper raceme; lanceolate; 5-7 mm long; larger than fertile. Basal sterile spikelet glumes glabrous, or villous; ciliate on margins; lower glume muticous. Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 5-6 mm long; longer than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; glabrous, or pubescent, or villous; acute; muticous, or mucronate, or awned; one glume awned; with 0.5-1.5 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1 mm long; pubescent; base obtuse, or acute; attached obliquely.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; yellow, or dark brown, or purple; without keels; keel-less except near apex. Lower glume surface glabrous, or hispidulous, or villous. Lower glume apex dentate; 2 -fid. Upper glume linear; coriaceous; without keels.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of fertile lemma; hyaline; 2 -veined. Fertile lemma linear; membranous; without keel; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; (1-)8-20(-28) mm long overall; with twisted column. Column of lemma awn puberulous, or pubescent; with 0.2-0.4 mm long hairs. Palea absent or minute.

Morphology Reproductive morphology Flowers

Lodicules 2; cuneate; fleshy. Anthers 3. Stigmas 2.

Distribution

Africa: west-central tropical, northeast tropical, east tropical, southern tropical, and south. Asia-temperate: Arabia. Pacific: north-central.

Reference

Andropogoneae. WDC.