GRAMINEAE (GRASS FAMILY) 67 



baceous with membranaceous margins, nearly smooth, indistinctly 3-nerved, 

 slightly exceeding the very thin palet. Gram lance-oblong, yellow, nearly 

 opaque. 



Panicle dense . . 1. E. obtusata. 



Panicle lax . . . . . . . . , . . 2. E. pe.nnsylvanica. 



1. Eatonia obtusata (Michx.) Gray Man. 558. 1856. Culms 4-8 dm. high: 

 panicle 1-2 dm. long; branches short, erect: spikelets short-pediceled, about 

 2.5 f mm. long: upper glume broadly obovate, obtuse, exceeding the lower, 

 nearly one third shorter than the lower floret; lemma slightly exceeding the 

 palet. Aira obtusata Michx. Moist land, central Texas to Minnesota and 

 eastward. Var. robusta Vasey is robust and scabrous throughout (5-10 dm. 

 high), with panicle dense, interrupted spike-like, and spikelets about 3 mm. 

 long. Frequent in our range; across the continent. 



2. Eatonia pennsylvanica (DC.) Gray, 1. c. Culms 5-10 dm. high: panicle 

 1-2 dm. long, often slightly nodding; branches ascending: spikelets 3 mm. 

 long: empty glume oblong-obovate, often subacute, about equaling the lower 

 in length, one third shorter than the lower floret; lemma slightly exceeding 

 the palet. Extending through the northern part of our range from the east- 

 ward. 



50. KOELERIA Pers. 



Erect perennial grasses with simple culms, and numerous usually flat leaves 

 at the base. Spikelets 2-4-flowered, with an obscure naked pedicel-like rudi- 

 ment, compressed, awnless, short pediceled, in narrow subspicate panicles: 

 rachilla hispidulous, articulating above the glumes. Glumes lanceolate, acute 

 carinate, herbaceous with membranaceous margins, subequal, the first 1- 

 nerved, the second 3-nerved, nearly smooth, equaling or slightly exceeding 

 the thin, hyaline palet. 



1. Koeleria cristata (L.) Pers. Syn. 1: 97. 1805. Culms 3-6 dm. high: pani- 

 cle subspicate, sometimes interrupted near the base and usually tapering near 

 the apex: spikelets mostly 2-flowered, 4-6 mm. long: glumes about equaling 

 the lower floret; lemma acute or mucronulate. Very common in our range; 

 on hillsides and bench lands. 



51. CATABROSA Beauv. 



A creeping perennial aquatic grass, erect or spreading, with flat leaf-blades 

 and an open panicle with capillary branches. Spikelets 2, rarely 3-4-fl owered ; 

 the rachilla smooth, articulated between the flowers. Glumes thin, mem- 

 branaceous, broad, unequal, very obtuse; lemma nrm-membranaceous, obtuse 

 or barely 3-toothed, longer than the glumes, conspicuously 3-nerved; palet 

 2-keeled, about as long as its lemma. Stamens 3. Styles distinct. Gram 

 obovoid-oblong. 



1. Catabrosa aquatica (L.) Beauv. Agrost. 97. 1812. Stems 1-5 dm. high, 

 rather stout, ascending: leaves 5-15 cm. wide, scabrous on the margin: panicle 

 uniform, branchlets numerous, divided: flowers light brown: glumes pur- 

 plish. In the Rocky Mountains. 



52. MELICA L. 



Slender leafy perennial grasses with large spikelets. Panicle open. Spike- 

 lets short-pediceled and somewhat racemose along the few branches, 3-12- 

 flowered, oblong or conical, awnless; the upper 1-5 florets imperfect, unlike the 

 lower perfect ones and convolute around each other forming a clavate or ob- 

 long rudiment. Glumes thin, broad, the upper usually larger, 7-9-nerved;- 

 lemma ovate, scarious at the obtuse or subacute apex, 5-15-nerved, one third 

 longer than the palet. Grain oblong or broadly spindle-shaped, channeled, 

 opaque. 



