114 POACEAE 



50. ANTHOXANTHUM L. 



Erect aromatic annual or perennial grasses, with flat leaf-blades and terminal usually 

 dense spike-like panicles. Spikelets articulated above the empty scales, 1-flowered, nar- 

 row, a little compressed, crowded. Scales 5, the 2 outer persistent, empty, acute, mu- 

 cronate, or short-awned, the second longer than the others, the third and fourth scales 

 much shorter, empty, narrow, keeled, awned at the middle or near the base, the fifth 

 scale shorter than the remainder, hyaline, obtuse, awnless, enclosing a 1-nerved palet and 

 a perfect flower. Stamens 2. Styles distinct. Stigmas elongated, plumose. 



1. Aiithoxaiithum odoratum L. Stems 3-6 dm. tall, erect, tufted : leaf-blades 1-15 

 cm. long, 2-6 mm. wide : panicle 2-6 cm. long : spikelets 8 mm. long. 



In fields and meadows throughout nearly the whole of North America. Naturalized from Europe. 

 Summer. SWEET VERNAL GRASS. 



51, SAVASTANA Schrank. 



Aromatic perennial grasses, with flat leaf-blades and contracted or open panicles. 

 Spikelets 3-flowered, the terminal flower perfect, the others staminate. Scales 5 ; first and 

 second nearly equal ; third and fourth a little shorter, awned or awnless, enclosing a palet 

 and stamens ; fifth scale, often with a short awn, enclosing a palet and a perfect flower. 

 Stamens in the staminate flowers 3, in the perfect 2. Styles distinct. Stigmas plumose. 



1. Savastana odorata (L. ) Scribn. Stems 3-6 dm. tall, simple: leaf-blades gla- 

 brous ; blades on the innovations 1-3 dm. long, 2-6 mm. wide, those on the stem 1-5 cm. 

 long, broad : panicle 5-10 cm. long, its branches usually spreading, naked at the base : 

 spikelets 4-6 mm. long. 



In moist or wet places, Newfoundland and New Brunswick to British Columbia, and in or near 

 the mountains to North Carolina (according to Chapman), Arizona and Mexico, and Oregon. Spring 

 and summer. VANILLA GRASS. HOLY GRASS. 



52. ARISTIDA L. 



Tufted grasses, with narrow and often convolute or setaceous leaf -blades and contracted 

 or open panicles, which are sometimes nearly racemose. Spikelets 1-flowered, narrow. 

 Scales 3, the outer 2 membranous, persistent, empty, narrow, keeled, awnless, usually 

 longer than the third scale which is of firmer texture, narrow, rigid, strongly convolute 

 about the 2-nerved palet and the perfect flower, often with a prominent callus at the base, 

 3-awned from the apex, the generally spreading awns glabrous to plumose, the central awn 

 commonly flexuous, coiled, or bent, the lateral awns often shorter, occasionally very short 

 and erect, the 3 awns sometimes more or less connate at the base and the column thus pro- 

 duced articulated to the scale. Stamens 3. Styles distinct. Stigmas plumose. POVERTY 

 GRASS. WIRE GRASS. 



A. Awns not articulated to the scale. 

 Central awn coiled at the base. 



First scale usually equalling or soinetimes slightly shorter than the second 



scale which is generally 7-9 mm. long. 1. A. dichotoma. 



First scale much shorter than the second (often but little more than % as 



long) which is 10-15 mm. long. 



Lateral awns short, straight and erect, 1-2 mm. long, the central awn 

 usually more than five times their length, its straight portion 5-8 

 mm. long. 2. A. Curtissii. 



Lateral awns more or less spreading, usually a little spiral at the base, 

 the central awn from % again to twice their length, its straight por- 

 tion from 10-15 mm. long. 3. A. basiramea. 

 Central awn not coiled at the base. 



a. Panicle narrow, linear to oblong, the branches generally short (or the 

 lower ones in No. 24 commonly elongated and ascending), usually erect 

 or ascending, sometimes spreading. 

 Central awn and sometimes the lateral ones also strongly reflexed, the 



bend semicircular. 

 Stems simple or nearly so : spikelets many, the first scale 1-nerved, or 



sometimes with an additional faint nerve on each side. 

 Spikelets less than 1 cm. long, the first scale strongly hispidulous. 

 the lateral awns of the flowering scale much more slender than 

 the central awn. 4. A. simplicifloru. 



Spikelets more than 1 cm. long, the first scale glabrous, the lateral 



awns about as stout as the central one. 5. A. Mokrii. 



Stems much branched : spikelets few, the first scale 5-7-nerved. 6. A. ramosissima. 



Central awn from erect to spreading with no semicircular bend at the 



base. 

 * First scale much shorter than the second, usually about y, as long. 



