Grasses of the Intermountain Region

STIPEAE

22 5. STIPEAE 5. STIPEAE Dumort. Mary E. Barkworth Pl usu per; usu tightly to loosely csp, smt rhz. Clm ann or per, not woody, smt brchg at up nd. Lvs bas concentrated to evenly distributed; shth open, mrg not fused, smt ciliate distally, bas shth smt concealing axillary pan (cleistogenes), smt wider than the bld; col smt with tufts of hair at the sides; aur absent; lig scarious, often ciliate, cilia usu shorter than the membranous base, lig of the lo and up cauline lvs smt differing in size and vestiture; psdpet absent; bld linear to narrowly lanceolate, venation parallel, cross venation not evident, cross sections non-Kranz, without arm or fusoid cells; epdm of adx surfaces smt with unicellular microhairs, cells not papillate. Infl usu tml pan, occ rdcd to rcm in depauperate pl, smt 2–3 pan developing from the highest cauline nd. Spklt usu with 1 flt, smt with 2–6 flt, lat compressed to terete; rchl not prolonged beyond the base of the flt in spklt with 1 flt, prolonged beyond the base of the distal flt in spklt with 2–6 flt, prolongation hairy, hairs 2–3 mm; dis above the glm and beneath the flt. Glm usu exceeding the flt(s), always longer than ¼ the length of the adjacent flt, 1–10-veined, narrowly lanceolate to ovate, hyaline or memb, flexible; flt usu terete, smt lat or dorsally compressed; cal usu well developed, rounded or blunt to sharply pointed, often antrorsely strigose; lm lanceolate, rectangular, or ovate, memb to coriaceous or indurate, 3–5-veined, veins inconspicuous, apc entire, bilobed, or bifid, awned, lm-awn jnct usu conspicuous, awns 0.3–30 cm, not brchd, usu tml and centric or eccentric, smt subtml, caducous to persistent, not or once- to twice-geniculate, if geniculate, proximal segment(s) twisted, distal segment straight, flexuous, or curled, not or scarcely twisted; lod 2 or 3; anth 1 or 3, smt differing in length within a flt; ov glab throughout or pubescent distally; sty 2(3–4)-brchd. Car ovoid to fusiform, not beaked, pericarp thin; hila linear; emb less than 1/3 the length of the car. x = 7, 8, 10, 11, 12. The tribe Stipeae includes 15–25 genera and 550–610 species. It grows in Africa, Australia, South and North America, and Eurasia. In Australia, South America, and Asia, it is often the dominant grass tribe over substantial areas. Most species grow in arid or seasonally arid, temperate regions. In a presentation to the Fourth International Conference on The Comparative Biology of the Monocotyledons, Romaschenko et al. (2008) argued that all the North American Stipeae are more closely related to the South American Stipeae than to the Asian Stipeae, but they have not as yet published the names that reflect their findings. Of the genera native to the Intermountain Region, the two that will be affected are Achnatherum and Piptatherum. 1. Paleas sulcate, longer than the lemmas; lemma margins involute, fitting into the paleal groove; lemma apices not lobed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.04 Piptochaetium 1. Paleas flat, from shorter than to longer than the lemmas; lemma margins convolute or not overlapping; lemma apices often lobed or bifid. 2. Lemma margins strongly overlapping their whole length at maturity, lemma bodies usually rough throughout, lemma apices not lobed. 3. Awns persistent; upper leaf blades longer than 2 cm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.06 Nassella 3. Awns deciduous; upper leaf blades shorter than 1.5 cm . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.05 Oryzopsis 2. Lemma margins usually not overlapping their whole length or only slightly so, strongly overlapping in some species with smooth, glabrous lemma bodies; lemma bodies usually smooth at least on the lower portion, apices 1–2-lobed; paleas from 1/3 as long as to equaling or slightly exceeding the lemmas, 2-veined, at least on the lower portion, usually hairy or both lemma and palea glabrous. 4. Awns once-geniculate, the basal section hairy with hairs 3–8 mm long, the distal section straight, scabrous or scabridulous; ligules of basal leaves densely hairy, those of upper leaves glabrous or almost so . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.07 Pappostipa 4. Awns not, once-, or twice-geniculate, the basal portion scabridulous, scabrous, or with hairs shorter than 2 mm, the distal portion straight or wavy, scabridulous to scabrous, sometimes with hairs up to 3 mm long; ligules of basal and upper leaves glabrous. 5. Calluses 1.5–6 mm long, sharply pointed; awns 65–225 mm long; paleas about as long as the lemmas, with a “pinched” top...