Poaceae
Hyparrhenia

Hyparrhenia pilosa Mazade

First published in Adansonia, n.s., 18: 138 (1978)
This species is accepted
The native range of this species is Central African Republic. It is a perennial and grows primarily in the seasonally dry tropical biome.

Descriptions

Morphology General Habit
Perennial. Culms erect; 150 cm long. Leaves cauline. Leaf-sheaths mostly shorter than adjacent culm internode. Ligule an eciliate membrane; 3 mm long. Leaf-blades 25-45 cm long; 3-6 mm wide.
Morphology Reproductive morphology Inflorescences
Synflorescence compound; paniculate. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole linear; 7-8 cm long; membranous. Peduncle pilose above. Racemes 2; paired; deflexed; 2.3 cm long; bearing few fertile spikelets; bearing 2-4 fertile spikelets on each. Rhachis fragile at the nodes; villous on margins. Rhachis hairs red; 2-3 mm long. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases filiform; unequal (the longer measured); 2-2.5 mm long; pilose. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 3.5-4 mm long; villous; with red hairs; with 2-3 mm long hairs; tip oblique; toothed (0.3-0.6 mm).
Morphology Reproductive morphology Inflorescences Spikelets
Basal sterile spikelets well-developed; on lower raceme 2 in number; 2 in upper raceme; lanceolate; 5.5-7.5 mm long; smaller than fertile. Basal sterile spikelet glumes hirsute; with red hairs; lower glume muticous. Companion sterile spikelets well-developed; lanceolate; dorsally compressed; 6-8 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; 13-15 -veined; hirsute; acute; muticous, or mucronate. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; 7-9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 2-2.5 mm long; pubescent; base pungent; attached obliquely.
Sterile
Basal sterile spikelets well-developed; on lower raceme 2 in number; 2 in upper raceme; lanceolate; 5.5-7.5 mm long; smaller than fertile. Basal sterile spikelet glumes hirsute; with red hairs; lower glume muticous. Companion sterile spikelets well-developed; lanceolate; dorsally compressed; 6-8 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; 13-15 -veined; hirsute; acute; muticous, or mucronate.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; 7-9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 2-2.5 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; coriaceous; without keels; keel-less except near apex. Lower glume surface hirsute. Lower glume hairs red; 3-4 mm long. Lower glume apex truncate. Upper glume lanceolate; coriaceous; without keels. Upper glume surface hirsute; hairy above. Upper glume apex acute.
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined; ciliate on margins; fringed above; truncate. Fertile lemma linear; membranous; without keel. Lemma margins ciliolate. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 40-75 mm long overall; with twisted column. Column of lemma awn ciliate (rufously); with 2 mm long hairs.
Distribution
Africa: west-central tropical.
Reference
Andropogoneae. Mazade 2005.
[GB]

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: threatened. Confidence: confident
[AERP]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • GrassBase - The Online World Grass Flora

    • Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H. (2006 onwards). GrassBase - The Online World Grass Flora.
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0