Cenchrus setigerus Vahl

synonyms: Cenchrus setiger, Cenchrus biflorus, Cenchrus montanus


cow sandbur


Info

Subfamily: Panicoideae
Genus etymology: Cenchrus = "millet" [Greek]. However this is a misnomer, the only millet species in this genus is C. americanus, and this was treated as Pennisetum when Cenchrus was erected.
Species etymology: setigerus = "bristle bearing" [Latin] refering to the bristles subtending the florets
Photosynthetic type: C4 (warm season)
Nativity: naturalized - intentional
First recorded in Hawaiʻi: 1936

Map

 Distribution of Cenchrus setigerus in Hawaiʻi.

Inflorescence

Cenchrus setigerus Inflorescence
Cenchrus setigerus Inflorescence
Cenchrus setigerus Inflorescence

Plant

Cenchrus setigerus Plant

Habit

Cenchrus setigerus Habit
Cenchrus setigerus Habit
Cenchrus setigerus Habit

Spikelets

Cenchrus setigerus Spikelets
Cenchrus setigerus Spikelets
Cenchrus setigerus Spikelets

Description

Perennial, forming clumps from a ± bulbous base; culms 5–80 cm. high, geniculately ascending. Leaf-blades 2–20 cm. long, 2–7 mm. wide. Panicle 2–12 cm. long; involucres cup-shaped, 3–7 mm. long; inner spines short, flattened, connate for 1/4–1/2 their length to form a cup, glabrous or obscurely puberulous and grooved on the face, occasionally sparsely ciliate on the margins, green to dark purple, antrorsely scaberulous, narrowly triangular at the tip; outer spines few, short, often suppressed, rarely almost as long as the inner. Spikelets 1–3 per burr, 3–5 mm. long.
(Description source: Clayton, W.D. & Renvoize, S.A. 1982. Flora of Tropical East Africa. Gramineae (Part 3). A.A. Balkema, Rotterdam. 448 pp. )

Perennial, forming clumps from a ± bulbous base, up to 80 cm high; leaves flat, 2–7 mm wide. Panicle 2–12 cm long; involucre cup-shaped, 3–7 mm long; inner spines short, flattened, connate for 1/4–1/2 their length to form a cup, glabrous or obscurely puberulous; outer spines few, short, often suppressed, rarely almost as long as the inner. Spikelets 1–3 per burr, 3–5 mm long.
(Description source: Cope, T.A, (1995) Flora Somalia, Vol 4. Royal Botanical Gardens, Kew, London. 312 pp. )

Habit: Perennial; caespitose. Butt sheaths thickened and forming a bulb. Culms geniculately ascending; 5-80 cm long. Ligule a fringe of hairs. Leaf-blades 2-20 cm long; 2-7 mm wide. Inflorescences: Inflorescence a panicle. Panicle spiciform; linear; 2-12 cm long. Primary panicle branches accrescent to a central axis; with sessile scars on axis. Panicle axis angular; bearing deciduous spikelet clusters. Spikelets subtended by an involucre. Fertile spikelets sessile; 1-3 in the cluster. Involucre composed of bristles; connate into a cup below; with 1-3 mm connate; oblate; 3-7 mm long; base obconical. Involucral bristles deciduous with the fertile spikelets; in one whorl, or with an outer whorl of thinner bristles; inner bristles longer than outer; with longest bristle scarcely emergent; 2-4 mm long; flattened; grooved on the face; rigid; antrorsely scaberulous; glabrous, or pubescent, or ciliate; obtuse, or spinose. Spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 3-5 mm long; falling entire; deciduous with accessory branch structures. Fertile Spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 3-5 mm long; falling entire; deciduous with accessory branch structures. Glumes: Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1.5-2 mm long; 0.5 length of spikelet; hyaline; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume surface puberulous. Lower glume apex obtuse, or acute. Upper glume ovate; 2 mm long; 0.5-0.66 length of spikelet; hyaline; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume surface puberulous. Upper glume apex obtuse, or acute. Florets: Basal sterile florets barren; with palea. Lemma of lower sterile floret oblong; 1 length of spikelet; membranous; 5 -veined; puberulous; emarginate; mucronate. Fertile lemma ovate; 3-5 mm long; chartaceous, or coriaceous; much thinner on margins; without keel; 5-7 -veined. Lemma margins flat. Lemma apex truncate, or obtuse; mucronate. Palea chartaceous, or coriaceous. Flowers: Lodicules absent. Anthers 3; 2 mm long. Fruits: Caryopsis with adherent pericarp; oblong; dorsally compressed; 1.5 mm long; truncate. Distribution: Africa: north, west tropical, northeast tropical, and east tropical. Asia-temperate: western Asia, Arabia, and China. Asia-tropical: India and Indo-China. Australasia: Australia. Pacific: north-central. South America: Brazil.
(Description source: Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H. (2006 onwards). GrassBase - The Online World Grass Flora. Available at https://powo.science.kew.org )