S1
Critically Imperiled
Panicum mohavense (Mohave Panicum)
Annual, much branched at base, 2-8 cm tall; culms erect, with 1 node, papillose-pilose, mostly obscured by the leaves; leaves with prominently veined, papillose-pilose sheaths; ligules 0.2 mm long, membranous and with short hairs; blades 1-4 cm long,...
Paronychia wilkinsonii (Wilkinson's Nailwort)
Small, cushion-forming perennial herb with a branched caudex; stems erect or ascending, 2.5-6(-10) cm high, hirtellous, mostly obscured by the opposite leaves; stipules lanceolate, scarious, 5-8 mm long and generally equaling the leaves, to 1.5 mm wi...
Pediocactus knowltonii (Knowlton Cactus)
Stems 1.0-2.5 cm in diameter, solitary or a few in a cluster, barely protruding above ground level; tubercles not grooved; spines about 20 per areole, all radials, radiating from areole and appressed to the plant, 1-2 mm long, usually whitish, pinkis...
Pediomelum pentaphyllum (Chihuahua Scurfpea)
Perennial herb up to about 25 cm tall, grayish-hairy with straight hairs that lie against the surface of the foliage; stems with a thin, cord-like, easily broken, subterranean portion bearing a few small bracts, and a very short aerial, leafy portion...
Penstemon bleaklyi (Bleakly's beardtongue)
Plants perennial, forming loose mats from numerous branched and tangled woody rhizomes; stems ascending-decumbent, 2-8 cm tall, minutely puberulent; stem leaves opposite, sessile, glabrous or with a few trichomes at the base, entire to serrulate, nar...
Penstemon metcalfei (Metcalfe's Penstemon)
Perennial from a slender, creeping, woody rhizome; stems few, usually erect, up to 4 dm high, puberulent throughout, glandular above; leaves entire, the lower ovate, the upper lanceolate, thin, minutely puberulent, amplexical, the upper sessile, the ...