Biorepository Data Portal

FNA 2003, Gould 1980, Kearney and Peebles 1969

Common Name: Mexican panicgrass Duration: Annual Nativity: Native Lifeform: Graminoid General: Annual grass, 20-110 cm tall; stems erect to decumbent, the nodes glabrous or shortly hirsute; herbage glabrous or hispid with papillose-based hairs. Vegetative: Sheaths shorter than the internodes, greenish to purplish, glabrous or with papillose-based hairs, ciliate on one margin and glabrous on the other; collars hirsute; ligules of hairs, 1-3 mm; blades flat with clasping bases, 3-30 cm long, 3-30 mm wide, usu Inflorescence: Panicles 9-30 cm long, 5-8 cm wide, erect or nodding, primary branches divergent, secondary branches and pedicels appressed, confined to the distal 2/3 of the primary branches; spikelets 2-4 mm long, ovoid, reddish-brown with prominent veins, 2-flowered, the first floret reduced to a sterile lemma and the second floret fertile. Lower glumes 3-5-veined; upper glumes 7-11-veined; lower lemmas similar to the upper glumes, 9-veined; upper lemma indurate, 2 mm long, ellipsoid, smooth or conspicuously papillate, shiny, stramineous. Ecology: Found on dry slopes and plains, sandy washes, and open woodlands below 7,000 ft (2134 m); flowers July-October. Distribution: OR south to NV and CA, east to TX and OK; south to S. Amer. Notes: The genus Panicum is defined as having unawned spikelets with 2 florets, the first floret sterile or staminate, and the second floret bisexual with a rigid lemma that clasps the palea. P. hirticaule is an erect to decumbent annual with broad, flat leaves; a panicle that is about <1/3 of the stem length; an acute 1st glume (see illustration) and spikelets, <4 mm long. Like many of the annual Panicum spp. in AZ, this species was once classified as a variety of P. capillare (Gould 1951). It is distinguished from P. capillare by its shorter pedicels < 8 mm long and its panicle branches that tend to be more stiff, straight, and ascending rather than gently curving and widely diverging as in P. capillare. FNA recognizes 3 varieties, all found in the Southwest. P. h. var . hirticaule is most common, with blades rounded at the base; lower paleas less than 1/2 as long as the upper florets; and erect panicles. P. hirticaule var. stramineum has blades with a clasping base; panicles often nodding; herbage glabrous or sparsely pilose; culms < 70 cm tall; and spikelets 3.2-4. mm. P. h. var. sonorum has blades with a clasping base; panicles often nodding; hirsute herbage; culms > 70 cm tall; and spikelets 3-3.3 mm. Ethnobotany: Seeds were ground into a meal and used for making flour and bread by the Cocopa. Etymology: Panicum is a classical Latin name for millet, hirticaule means hairy-stemmed. Synonyms: Panicum pampinosum, P. alatum and others, see Tropicos Editor: SBuckley 2010, FSCoburn 2014, AHazelton 2015