Panicum capillare Linn., Sp. Pl. 1:58. 1753. Bor in Rech.f., Fl. Iran. 70:470. 1970; Tzvelev, Poaceae URSS 660.1976; Clayton in Tutin et al., Fl. Fur. 5:261. 1980.
Tufted, densely hispid annual (rarely almost glabrous); culms 20-80 cm high, erect or ascending. Leaf-blades linear to narrowly lanceolate, 7-30 cm long, 5-14 mm wide, flat, sharply pointed. Panicle broadly ovate or broadly oblong, 15-50 cm long, the branches filiform, bearing spikelets on long capillary pedicels, the whole inflorescence eventually disarticulating. Spikelets elliptic or oblong, 1.8-2.5(3.3) mm long, glabrous, acute or acuminate; lower glume broadly ovate, membranous, a third to half the length of the spikelet, 3-nerved, obtuse, acute or slightly acuminate; upper glume 5-7-nerved; lower lemma 5-7-nerved, its palea about half as long; upper lemma pallid or yellowish to olive-brown, smooth and shining.
Fl. & Fr. Per.: July-August.
Type localities: Virginia, U.S.A. and Jamaica.
Distribution: Pakistan (Baluchistan; naturalised); North America.
Witch grass is a North American species that was apparently accidentally introduced to Pakistan and is now fully established as a weed of cultivated ground ground Ziarat. It belongs to that group of plants, along with Panicum turgidum, known as tumble-weeds. The whole inflorescence breaks off at maturity and is blown about by the wind, scattering its seeds as it goes. The plants in Pakistan belong to var. occidentale Rydb. in Contr. U.S. natn. Herb. 3:186. 1895 (Bor, Grasses Burma Ceyl. Ind. Pak. 332. 1960) differing from the type by their larger spikelets.