Hyparrhenia niariensis (Franch.) Clayton

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

Morphology General Habit

Annual; culms up to 200 cm high, glabrous, supported by stilt roots.

Morphology Leaves Leaf sheaths

Leaf sheaths glabrous, or pubescent along the margins; leaf laminas up to 60 cm × 15 mm, glabrous or sometimes pubescent beneath, narrowed to the midrib at the base and sometimes falsely petiolate.

Morphology Reproductive morphology Inflorescences

False panicle 30–50 cm long, lax, leafy; spatheoles 3–5 cm long, narrowly lanceolate, glabrous or sparsely pilose; peduncles about as long as the spatheoles, barbate all round with yellow bulbous-based hairs, ± straight; racemes 1.5–1.8 cm long, 2-awned per pair (rarely 3-awned but not in the Flora Zambesiaca area), terminally or subterminally exserted, deflexed; raceme-bases subequal, the superior 1–1.5 mm long, flattened, stiffly setose with fulvous bulbous-based bristles, the apex produced into an oblong or narrowly oblong appendage 0.5–4 mm long.

Homogamous

Homogamous spikelets 9–11 mm long, a single pair at the base of the inferior raceme only, glabrous, awnless.

Sessile

Sessile spikelets 7.5–11 mm long; callus 2–3 mm long, pungent; inferior glume linear-oblong, often shallowly hollowed on the back, ± pubescent; awn 6.5–8.5(10.5) cm long, the column pubescent with pale or rufous hairs 0.2–0.6 mm long.

Morphology Reproductive morphology Inflorescences Spikelets

Pedicelled spikelets 8–13 mm long, linear-lanceolate, glabrous, terminating in a slender bristle 2–10 mm long; callus scarcely developed; pedicel-tooth obscure. Sessile spikelets 7.5–11 mm long; callus 2–3 mm long, pungent; inferior glume linear-oblong, often shallowly hollowed on the back, ± pubescent; awn 6.5–8.5(10.5) cm long, the column pubescent with pale or rufous hairs 0.2–0.6 mm long. Homogamous spikelets 9–11 mm long, a single pair at the base of the inferior raceme only, glabrous, awnless.

Pedicelled

Pedicelled spikelets 8–13 mm long, linear-lanceolate, glabrous, terminating in a slender bristle 2–10 mm long; callus scarcely developed; pedicel-tooth obscure.

Morphology General Habit

Annual. Butt sheaths glabrous. Culms erect; 100-200 cm long; with prop roots. Leaves cauline. Ligule an eciliate membrane. Leaf-blade base tapering to the midrib; without a false petiole, or with a false petiole. Leaf-blades 30-60 cm long; 7-15 mm wide. Leaf-blade surface glabrous, or pubescent; hairy abaxially.

Morphology Reproductive morphology Inflorescences

Synflorescence compound; paniculate; 30-50 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted. Spatheole lanceolate; 3-5 cm long; membranous; glabrous, or pilose. Peduncle 3-5 cm long; pilose above. Racemes 2; paired; deflexed; 1.5-1.8 cm long; bearing few fertile spikelets; bearing 1(-2) fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases flattened; subequal; 0.5-1.5 mm long; stiffly setose (yellow hairs); scariously rimmed (rarely), or extended into an oblong appendage; with (0.2-)0.5-4 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; 9-11 mm long; equalling fertile. Basal sterile spikelet glumes glabrous; smooth on margins; lower glume muticous. Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 8-13 mm long; longer than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; awned; one glume awned; with 2-10 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 7.5-11 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 2-3 mm long; pubescent; base pungent; attached obliquely.

Sterile

Basal sterile spikelets well-developed; on lower raceme 2 in number; 0 in upper raceme; lanceolate; 9-11 mm long; equalling fertile. Basal sterile spikelet glumes glabrous; smooth on margins; lower glume muticous. Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 8-13 mm long; longer than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; awned; one glume awned; with 2-10 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 oblong; dorsally compressed; 7.5-11 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 2-3 mm long; pubescent; base pungent; 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; chartaceous, or coriaceous; without keels; keel-less except near apex. Lower glume surface convex, or concave; glabrous. Lower glume apex dentate; 2 -fid. Upper glume linear; chartaceous, or 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; 65-85(-105) mm long overall; with twisted column. Column of lemma awn pubescent. Palea absent or minute.

Morphology Reproductive morphology Flowers

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

Morphology Reproductive morphology Fruits

Caryopsis 4 mm long.

Distribution

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

Reference

Andropogoneae. WDC.

Diagnostic

Peduncle hairs yellow.

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, W. D. Clayton, S. M. Phillips & S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit

Annual; culms 1–2 m. high, supported by stilt roots.

Morphology Leaves

Leaf-blades up to 60 cm. long, 15 mm. wide.

Morphology Reproductive morphology Inflorescences

False panicle loose, leafy, 30–50 cm. long; spatheoles narrowly lanceolate, 3–5 cm. long, the peduncles about as long and bearded above with yellow (rarely white) hairs; racemes 1.5–1.8 cm. long, 2- or sometimes 3-awned per pair, deflexed; raceme-bases subequal, flattened, stiffly setose, the tip produced into a scarious oblong appendage 0.5–4 mm. long, Homogamous pairs 1 at the base of the lower raceme only.

Morphology Reproductive morphology Inflorescences Spikelets

Sessile spikelet 7.5–11 mm. long, pallid, ± pubescent; callus 2–3 mm. long, pungent; awn 6.5–8.5(–10.5) cm. long. Pedicelled spikelet with an awnlet 2–10 mm. long.

Sessile

Sessile spikelet 7.5–11 mm. long, pallid, ± pubescent; callus 2–3 mm. long, pungent; awn 6.5–8.5(–10.5) cm. long.

Pedicelled

Pedicelled spikelet with an awnlet 2–10 mm. long.

Habitat

Wooded grassland; 760–1200 m.

Distribution

T4 U1 western Africa from Cameroun to Angola