Cymbopogon obtectus S.T.Blake

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

Morphology General Habit

Perennial; caespitose. Butt sheaths pubescent; persistent and investing base of culm. Culms 50-100 cm long; 1-2 -noded. Culm-nodes glabrous, or pubescent. Ligule an eciliate membrane; 3-5 mm long. Leaf-blades flat, or conduplicate, or revolute; 15-35 cm long; 1.25-2.5 mm wide; aromatic. Leaf-blade margins scaberulous. Leaf-blade apex attenuate.

Morphology Reproductive morphology Inflorescences

Synflorescence compound; linear, or paniculate; 7-25 cm long; dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole 2-3.2 cm long; herbaceous. Peduncle 0.5-1 cm long. Racemes 2; paired; deflexed; 1.5-2.5 cm long. Rhachis fragile at the nodes; semiterete; villous on surface; villous on margins. Rhachis hairs 4.5-7 mm long. Rhachis internodes linear; 2.75-3.5 mm long. Rhachis internode tip transverse; cupuliform. Raceme-bases flattened; subequal. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; semiterete; 2.75-3.5 mm long; villous; with 4.5-7 mm long hairs.

Sterile

Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme; sessile and pedicelled. Basal sterile spikelet pedicels free; linear. Basal sterile spikelets barren (lacking florets); equalling fertile. Companion sterile spikelets well-developed; comprising 2 unequal glumes without lemmas, or containing empty lemmas; lanceolate; 3.5-5 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; 11-13 -veined; glabrous; acute; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; acute; 5.2-6.4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse; inserted. Spikelet callus hairs 4-5 mm long. Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme; sessile and pedicelled. Basal sterile spikelet pedicels free; linear. Basal sterile spikelets barren (lacking florets); equalling fertile. Companion sterile spikelets well-developed; comprising 2 unequal glumes without lemmas, or containing empty lemmas; lanceolate; 3.5-5 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; 11-13 -veined; glabrous; acute; muticous. 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; acute; 5.2-6.4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse; inserted. Spikelet callus hairs 4-5 mm long.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; chartaceous; 2-keeled; keeled laterally; wingless. Lower glume intercarinal veins distinct; 2-5 in number. Lower glume surface concave. Lower glume apex acuminate. Upper glume lanceolate; 1-keeled; keeled above; 5-7 -veined. Upper glume margins ciliolate. Upper glume apex acute.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 3.7-4.5 mm long; hyaline; 2-3 -veined; ciliolate on margins; acute. Fertile lemma lanceolate; 3.6-4.5 mm long; hyaline; without keel; 1-3 -veined. Lemma apex lobed; 2 -fid; incised 0.15-0.33 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; straight, or geniculate; 6-8 mm long overall; without a column, or with a straight or slightly twisted column. Column of lemma awn glabrous. Palea absent or minute.

Morphology Reproductive morphology Flowers

Anthers 3; 1.7-2 mm long.

Morphology Reproductive morphology Fruits

Caryopsis with adherent pericarp; orbicular.

Distribution

Australasia: Australia.

Reference

Andropogoneae. Vickery.