[Eatonia Endlich. Gen. 99. 1837. Not Raf. 1819.]

Tufted perennial grasses, with flat or involute leaf-blades and usually contracted panicles. Spikelets 2-3-flowered, the rachilla extended beyond the flowers. Two lower scales empty, shorter than the spikelet, the first linear, acute, 1-nerved, the second much broader, 3-nerved, obtuse or rounded at the apex, or sometimes acute, the margins scarious; flowering scales narrower, generally obtuse. Palet narrow, 2-nerved. Stamens 3. Styles distinct, short. Stigmas plumose. Grain free, loosely enclosed in the scale and palet. [Greek, referring to the wedge-shaped second scale of the spikelet.]

A genus of 7 or 8 species, confined to North America. Type species: Aira obtusata Michx.

Empty scales unequal, the first shorter and about one-sixth as wide as the second.

Second scale obovate, often almost truncate.

1.

E. obtusata.

Second scale oblanceolate, obtuse or abruptly acute.

2.

E. pallctis.

Empty scales equal, the first not less than one-third as wide as the second.

3.

E. nitida.

81 Sphenopholis Scribn Rhodora 8 142 1906 586

1. Sphenopholis Obtusata (Michx.) Scribn. Early Bunch-Grass

Fig. 586

Aira obtusata Michx. Fl. Bor. Am. 1: 62. 1803. Eatonia obtusata A. Gray, Man. Ed. 2, 558. 1856. Eatonia pubescens Scribn. & Merr. Circ. U. S.

Dep. Agr. Agrost. 27: 6. 1900. E. robusta Rydb. Bull. Torr. Club 32: 602. 1905. S. obtusata Scribn. Rhodora 8: 144. 1906.

Culms i°-2 1/2° tall, erect, simple, often stout, smooth and glabrous. Sheaths shorter than the internodes, usually more or less rough, sometimes pubescent; ligule 1/2"-1" long; blades 1'-9' long, 1"-4" wide, scabrous; panicle 2'-6' in length, dense and generally spike-like, strict, the branches 1 1/2' long or less, erect; spikelets crowded, 1 1/4"- 1 1/2" long; empty scales unequal, often purplish, the first narrow, shorter than and about one-sixth as wide as the obtuse or almost truncate second one; flowering scales narrow, obtuse, 3/4"-1" long.

In dry soil, Maine to Saskatchewan, Florida and Arizona. Prairie-grass. June-Aug.

2. Sphenopholis Pallens (Spreng.) Scribn. Tall Eaton's Grass

Fig. 587

Aira pallens Spreng. Fl. Hal. Mant. 33. 1807. Eatonia pennsylvanica A. Gray, Man. Ed. 2, 558, in part. 1856. S. pallens Scribn. Rhodora 8: 145. 1906.

Usually glabrous, culms 1°-3° tall, erect, simple, slender, smooth. Sheaths shorter than the internodes; ligule 3/4" long; blades 2 1/2'-7' long, 1"-3" wide, rough; panicle 3'-/ in length, contracted, often nodding, lax, its branches 1'-2 1/2' long; spikelets 1 1/2"-1 3/4" long, usually numerous, somewhat crowded and appressed to the branches; empty scales unequal, the first narrow, shorter than and about one-sixth as broad as the obtuse or abruptly acute second one, which is smooth, or somewhat rough on the keel; flowering scales narrow, acute, 1 1/4" long, rarely awned.

In hilly woods or moist soil, Newfoundland to British Columbia, Georgia and Texas. June-July.

2 Sphenopholis Pallens Spreng Scribn Tall Eaton s 5872 Sphenopholis Pallens Spreng Scribn Tall Eaton s 588

3. Sphenopholis Nitida (Spreng.) Scribn. Slender Eaton's-Grass

Fig. 588

Aira nitida Spreng. Fl. Hal. Mant. 32. 1807. Eatonia Dudleyi Vasey, Coult. Bot. Gaz. 11: 116. 1886. Eatonia nitida Nash, Bull. Torr. Club 22: 511. 1895. E. glabra Nash, in Britt. Man. 1043. 1901. S. nitida Scribn. Rhodora 8: 144. 1906.

Glabrous, culms 1°-2° tall, erect, very slender, smooth. Sheaths shorter than the internodes, generally pubescent; ligule 1/4" long; blades ¥-3' long, 1" wide or less, often pubescent, the uppermost very short; panicle 2'-6' in length, lax, the branches spreading at flowering time, afterwards erect, l'-2 1/2' long; spikelets not crowded, 1 1/2" long; empty scales smooth, the first about one-third as wide as and equalling the second, which is obtuse or almost truncate, often apiculate; flowering scales narrow, 1"-1 1/4" long, obtuse or acutish, smooth.

In dry woods. Vermont to Michigan, Georgia and Mississippi. May-June.