9b GRAMINEAE ([GRASS FAMILY^ 



spikelets solitary or in 2's, 2.2 mm. long ; the ghime and sterile lemma equals 



densely short-villons between the nerves, as long as the dark brown fertile lemma. 



{Panicum lineare Krock ; P. glabrum Gaud.) — Cultivated auc- 



A waste ground, N. S. to S. Dak., and southw. Aug.-Oct. (Kac. 



AJI from Eu.) Fig. 54. 



m 4. D. ser6tina Michx. Extensively creeping, forming dense 



\ mats ; the crowded sheaths pilose; blades 2-8 cm. long, 4-7 mm. 



wide, pilose on both surfaces; racemes 3-8, at the apex ot 



^s ^k ^T'^'d'''' ascending branches (1-3 dm. high), 3-10 cm. long; spikelets 



.pi-eetx . mostly in 2's, 1.6 mm. long., sparsely pubescent between the 



nerves; the glume scarcely | as long as the pale fertile lemma. (Panicum 



Trin.) — Low sandy ground near the coast, s. Pa., Del., and southw. June-Aug. 



-*- -»- Pedicels sharply angled; first glume present, minute, 



5. D. sanguinXlis (L.) Scop. (Crab Grass.) Culms erect or ascending 

 from a decumbent often creeping base, 3-12 dm. long ; 

 nodes and sheaths more or less papillose-hirsute ; blades 

 lax, 5-12 cm. long, 4-10 ram. wide, scabrous, often more 

 or less pilose ; racemes 3-12, subfasciculate, 5-18 cm. 

 long ; spikelets in pairs, 3-3.5 mm. long., usually appressed- 

 pubescent between the smooth or scabrous nerves ; second 

 glume about | as long as the pale or grayish fertile lemma. 

 (PanicnmLi.] Syntherismafimbriata^&sh.) — Cultivated 55. D. sanguinalis. 

 and waste grounds, throughout our range, and southw. Part of intlorescence x%. 

 Aug.-Oct Very variable. (Nat. from Eu.) Fig. 65. Spikelets x 3. 



7. LEPT0l6mA Chase 



Spikelets l-flowered, fusiform, solitary on long capillary 8-angled pedicels ; 

 first glume obsolete or very minute, the second 3-nerved, nearly as long as the 

 5-7-nerved sterile lemma ; fertile lemma cartilaginous-indurated, papillose, with 

 a delicate hyaline margin not inrolled, inclosing a palea of like texture ; grain 

 free within the lemma and palea. — Tufted perennials, with flat leaves and very 

 diffuse terminal panicles, which break away at maturity and become tumble- 

 weeds. (Name from XewTos, delicate, and Xw/^a, border, in reference to the 

 hyaline margins of the lemma.) 



1. L. cognatum (Schultes) Chase. (Fali. Witch Grass.) Pale gi'een, much 

 branched at the base, erect or geniculate below, very brittle, 3-7 dm. high ; 

 lower sheaths pilose, the upper usually glabrous ; ligule membranaceons, 1 mm. 

 long ; blades 5-8 cm. long, 4-6 mm. wide, rather rigid, usually glabrous, scabrous 

 on the margins ; panicle \-\ the entire height of the plant, short-exserted, very 

 diffuse, as broad as long or broader ; the capillary scabrous subflexuous 

 branches at first ascending, soon widely spreading, naked below, pilose in the 

 axils; spikelets on scabrous pedicels, 1-4 cm. long, acuminate, 2.7-3 mm. long; 

 glume and sterile lemma with a stripe of appressed silky pubescence between the 

 nerves and on the margins, or the hairs becoming loose and spreading especially 

 on the margins, very variable in the same panicle ; fruit acuminate, chestnut, 

 the margins of the lemma white. {Panicum Schultes; P. antnmnale Bosc.) 

 — Dry soil and sand hills, N. H. to Pla. ; 111. to Minn., southw. and south westw. 



8. AMPHICARPON Kunth 



Spikelets l-fiowered, of 2 kinds, one in a terminal panicle, p<3rfect but nol 

 fruitful, the other subterranean, cleistogamous, on slender leafless stems at the 

 bas ■ of the culm ; the fust glume of the aerial spikelets variable in size or obso- 

 lete ; the second and tlie sterile lemma subequal ; lemma and palea indnratfcl. 

 marmr.s of lemma reitlier hyaline nor inrolled ; clei-stogamous spikelets mv.er 



