Tanglehead

Locally this grass is usually found in the southern parts of Taiwan along railways.

The narrowly cylindrical racemes of overlapping, green spikelets with stout, brown, intertwining awns emerging from the upper part are very characteristic of this species. It is a very widespread and extremely polymorphic species, varying in habit, hairiness of the spikelets, and also physiologically in response to differing rainfall regimes. It is apomictic and includes a range of chromosome numbers. The name Heteropogon fertilis has been applied to an atypical, stunted specimen lacking homogamous spikelet pairs at the base of the raceme. It was described from Yunnan, but similar forms with only a single homogamous spikelet pair are known from Hong Kong and elsewhere.

This species provides good forage when young, but the needle-sharp spikelet calluses can cause damage to livestock when mature. The leaves and stems are utilized in papermaking.

Speargrass is considered to be a good fodder grass before it reaches the flowering stage, and hay made from it is said to keep for many years. After flowering it is avoided by stock. Animals can be seriously injured by the sharp callus which, aided by the hygroscopic awns, can burrow into the flesh causing septic sores, lameness or more serious harm. Apart from the irritation having an adverse effect on the animals health, the commercial value of their hides is much reduced by these injuries.

Rhizome stout. Culms up to 60 cm high. Blades up to 15 cm long, scabrous; ligule ciliate, about 1 mm long; sheath compressed and keeled, longer than the internode. Raceme single, 3-6 cm long. Spikelets paired, basal 3-10 spikelets imbricate, sterile, persistent and awnless; upper 10 spikelets paired, one pedicellate, the other sessile. Sessile spikelets about 7 mm long, cylindrical, covered with brown hairs, awned from the summit, the awn long and stout; callus sharp pointed, about 2 mm long; glumes coriaceous, rounded on the back; upper glume 2-nerved, margins membranous; upper lemma linear, membranous, tipped with a genicula awn of 10 cm long, column twisted and hairy.

Untidily tufted perennial, the basal sheaths laterally compressed; culms 30-100 cm high, erect. Leaf-blades flat, 3-30 cm long, 2-8 mm wide, abruptly narrowed at the tip. Racemes 3-10 cm long, mostly long exserted, solitary or aggregated into a scanty false panicle, the awns forming a twisted spire. Homogamous spikelets 3-17 pairs, resembling the pedicelled spikelets. Sessile spikelet 5.5-10 mm long including a ferociously pungent and rufously bearded callus 2-3 mm long; lower glume elliptic-oblong, brown, hispidulous; awn 5-8 cm long, hirtellous. Pedicelled spikelet 5-15 mm long; lower glume green with yellowish membranous margins; the hairiness varying from glabrous to tuberculate-villous; callus 2-3 mm long.

Perennial. Culms slender, tufted, usually geniculate at base, 20–100 cm tall. Leaf sheaths keeled; leaf blades flat or folded, 10–20 × 0.3–0.6 cm, scabrid or adaxial surface pilose at base, apex obtuse or shortly acute to apiculate; ligule ciliate along margin. Inflorescence terminal or racemes gathered into a scanty panicle; spatheoles linear, tightly rolled around peduncle; peduncles mostly long-exserted. Racemes 3–7 cm (excluding awns), narrowly cylindrical, 7–12-awned, (1–)3–10(–12) pairs of flat green homogamous spikelets below the awned fertile pairs. Sessile spikelet 5–7 mm, dark brown; callus 2–3 mm, fiercely pungent, brown bearded; lower glume linear becoming cylindrical at maturity, sometimes hispidulous between veins; awn 6–10 cm, dark brown, column white-hirtellous, tips of successive awns often twisting together. Pedicelled spikelet 6–11 mm, lower glume oblong-lanceolate, greenish, laterally asymmetrically winged, glabrous or sparsely to densely pilose or tuberculate-hispid or white setose. Fl. and fr. Apr–Dec. 2n = 20, 40, 44, 50, 60, 80.

Widely distributed in tropics.

Widely distributed in the tropics, ascending in the Himalaya to 2,000 m.

Distribution: Pakistan (Sind, Baluchistan, Punjab, N.W.F.P. & Kashmir); tropical and warm temperate regions generally.

Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Henan, Hubei, Hunan, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [tropics and subtropics of the world, extending to Mediterranean and other warm-temperate areas].

400-2600 m

Fl. & Fr. Per.: June-October or November.

Dry hillsides, roadsides, grassy places, in the open or light shade; 400–4500 m.

Andropogon contortus Linnaeus, Sp. Pl. 2: 1045. 1753; Heteropogon fertilis B. S. Sun & S. Wang.

Andropogon corctortus L., Sp, Pl. 1045. 1753.
Heteropogon contortus Beauv. var. hispidissimus Honda, Bot. Mag. Tokyo 40: 105. 1926. Monogr. 336. 1930.

contortus: contorted, twisted

Heteropogon contortus (L.) Beauv.; R. & S. Syst
Veg. 2 : 836. 1817.
Andropogon coniortus ly. Sp. PI. 1045. 1753.
Heteropogon hirtus Pers. Syn. PI. 2 : 533. 1807.
Andropogon Allionii H.B.K. Nov. Gen. & Sp. 1 : 185. 1816. Not A . Allionii DC. 1805.
Andropogon secundus V^\&. Nees, Agrost. Bras. 364. 1829.
Heteropogon firmus 'i . Presl, in Presl, Rel. Haenk. 1 : 334.1830.
Andropogon firmus Kunth, Enum. 1 : 486. 1833.
Sorgum contortum Kuntze, Rev. Gen. 791. 1891.
Perennial. Stems 2-8 dm. tall, rather sparingly branched above; leaf-sheaths smooth, even on the keel; blades 2 dm. long or less, 3-7 mm. wide; racemes 4-7 cm. long, exserted or included at the base, the peduncles hispidulous, the internodes between the upper spikelets densely pubescent with long nearly appressed chestnut-brown hairs ; pistillate sessile spikelet 8-10 mm. long, including the brown-barbed callus which is about 3 mm. long, the awn 4.5-12 cm. long; pedicellate spikelet about 1 cm. long, empty or staminate, the first scale acute,, papillose-hispid with long hairs toward the summit and near the margins.
Type locality : India.
Distribution : Texas to Arizona and Honduras, and widely distributed in warm temperate and tropical regions generally.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Plants aromatic or malodorous, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath or blade keeled, 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, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence single raceme, fascicle or spike, Inflorescence branches 1-sided, Flowers bisexual, Flowers unisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets dorsally compressed or terete, Inflorescence or spikelets partially hidden in leaf sheaths, subtended by spatheole, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelets paired at rachis nodes, Spikelets in paired units, 1 sessile, 1 pedicellate, Pedicellate spikelet rudimentary or absent, usually sterile, Spikelets bisexual, Spikelets unis exual, Spikelets disarticulating below the glumes, Spikelets disarticulating beneath or between the florets, Spikelets conspicuously hairy , 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 surface hairy, villous or pilose, Glumes 8-15 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 3 nerved, Lemma apex acute or acuminate, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn 2-4 cm long or longer, Lemma awned from tip, Lemma awn twisted, spirally coiled at base, like a corkscrew, Lemma awn once geniculate, bent once, Lemma margins thin, lying flat, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Heteropogon contortus is a tropical, perennial tussock grass with a native distribution encompassing Southern Africa, southern Asia, Northern Australia, Oceania, and southwestern North America. The species has also become a naturalised weed in tropical and subtropical regions in the Americas and East Asia. The plant grows to 1.5 metres (4.9 ft) in height and is favoured in most environments by frequent burning. The plants develop characteristic dark seeds with a single long awn at one end and a sharp spike at the other. The awn becomes twisted when dry and straightens when moistened, and in combination with the spike is capable of drilling the seed into the soil.

The species is known by many common names, including black speargrass, tanglehead, steekgras (in Afrikaans) and pili (in Hawaiian, ultimately from Proto-Austronesian *pilit₁ "to adhere/stick"). H. contortus is a valuable pasture species across much of its range. However, it has also been responsible for the elimination of the wool industry over much of Australia due to the seeds becoming embedded in the wool and skin of sheep and devaluing the wool and killing the animals. H. contortus seeds are also responsible for similar injuries in dogs with thick undercoats, or becoming embedded in the socks and skin of hikers.