Chrysopogon aciculatus (Retz.) Trin.

It is one of the best soil and water conservation grasses occuring on the river banks and on exposed slopes.

Rarely, racemes of this species may have one or more spikelet pairs below the triad.

This is a ground-cover grass used for erosion control and lawns. It sometimes becomes a noxious weed. The needle-sharp callus on the diaspore can injure cattle and other animals, catching in fur and then penetrating the skin.

Rhaphis aciculatus (Retz.) Honda in Bot. Mag. Tokyo 40 103. 1926, Monogr. 335. 1930; Pilger in Engl., Pflanzcnf. ed. 2. 14e: 153. 1940. Perennials; culms rhizomatous and stoloniferous, long creeping, flowering culms erect. Ligule short, about 0.5 mm long. Inflorescence a panicle, 5-10 cm long, purplish, lower branches whorled; pedicelled spikelets about 6 mm long. Spikelets in threes, one sessile and perfect, the other 2 pedicellate and sterile. Sessile spikelets terete, lanceolate, about 4 mm long with a sharp, elongated callus of about 5 mm long; glume coriaceous, equal, as long as the spikelet; lower glume lanceolate, 7-nerved, upper half 2-keeled, hispidulous; lower part rounded on the back and glabrous; upper glume boat-shaped, slightly keeled and hispidulous near the apex, with a short straight awn, margins ciliate; upper lemma 1-nerved, with an awn of about 6 mm long; palea obtuse, 1/2 as long as the lemma; anthers about 1.3 mm long.

Perennial with extensively creeping rhizomes, sward forming; rhizomes stout, close-noded. Culms decumbent at base or ascending, 20–50 cm tall. Leaf sheaths glabrous or ciliate at mouth; leaf blades broadly linear, 3–5 × 0.4–0.6 cm, glabrous or adaxial surface pilose near base, margins serrate, apex subacute; ligule 0.1–0.3 mm. Panicle dense, oblong in outline, 5–9 cm, purplish brown; branches erect when dry, 1.5–3 cm, tipped by a single triad. Sessile spikelet 3.5–4 mm; callus acicular, 4–6 mm, bearded with golden hairs, obliquely attached to branch apex; glumes leathery; lower glume lanceolate, 2-keeled upward, lower back smooth, glabrous, upper back thinner, keels hispidulous, apex acute to 2-toothed; upper glume setulose on upper keel, acuminate or mucronate, mucro 1–2 mm; upper lemma entire, awned; awn straight, 4–7 mm. Pedicelled spikelet staminate, 4–5.7 mm; lower glume acuminate or with mucro to 1 mm. Pedicel 3/4 length of sessile spikelet, glabrous. Fl. and fr. Jun–Oct. 2n = 20.

Tropical Asia, Nepal, India, Ceylon, Burma, Indo-China, China, Malaysia, Polynesia, Australia.

Widely distributed in the tropics of Asia in hills and plains. An extremely common grass in village pastures on the plains where the prostrate creeping stems resist overgrazing.

Fujian, Guangdong, Guangxi, Guizhou, Hainan, Taiwan, Yunnan [Afghanistan, Bangladesh, Bhutan, Cambodia, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Singapore, Sri Lanka, Thailand, Vietnam; Australia, Pacific Islands (Polynesia)].

150-1700 m

Dry open grasslands, waste ground, lawns; 500–1000 m.

Andropogon aciculatus Retz., Obs. 5: 22. 1789.

Andropogon aciculatus Retzius, Observ. Bot. 5: 22. 1789; Centrophorum chinense Trinius.

Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stolons or runners present, Stems trailing, sprea ding or prostrate, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems mat or turf forming, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem nodes bearded or hairy, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solita ry, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelets 3 per node, Spikelets with 1 terminal fertile floret and 2 lateral staminate or sterile florets, Spikelets in paired units, 1 sessile, 1 pedicellate, Pedicellate spikelet rudimentary or absent, usually sterile, Pedicellate spikelet well developed, staminate, Spikelets bisexual, Spikelets unisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 4-7 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 1 nerved, Lemma 3 nerved, Lemma body or surface hairy, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awned from tip, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Palea membranous, hyaline, Palea shorter than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Chrysopogon aciculatus (syn. Andropogon aciculatus) is a species of grass native to the tropics of Asia, Polynesia, and Australia at low elevations. Common names include amorseco (Spanish, "dry love") (not to be confused with the amor seco tree, Alchornea glandulosa), lesser spear grass, Mackie's pest, pilipiliula, and grama-amorosa (Brazilian Portuguese).

The grass is widely considered an invasive species, but some cultures use it for medicinal purposes.

Its flowering stems are about 20 to 60 centimeters high and its leaves are linear-lanceolate and about 3 to 10 centimeters long by 4 to 6 centimeters wide. The panicles are purplish, open and with few whorled branches and can reach about 5 centimeters long, bearing few-flowered spikes. The sessile spikelet is very narrow, about 3 millimeters long. The callus is elongated and barbed and the fourth glume is linear, acuminate, and awned.

at Peradeniya Royal Botanical Garden