GRAMINEAE (G El ASS FAMILY) 105 



divergent densely flowered hranchlets mostly from the lower side ; spikelets2 mm. 

 long, crowded ; a few long hairs on the short pedicel ; second glume and sterile 

 lemma subequal. — Wet m.eadows and shores, Me. to Minn., 

 and southw. Aug., Sept. Fig. 62. 



14. P. stipitatum Nash. Similar to the preceding ; leaves 

 and panicles commonly dark purple, the latter narrower and 

 closer ; lateral panicles short-peduncled from the upper nodes ; 

 spikelets narrower, more pointed, distinctly secund upon the 

 hranchlets ; second glume longer than the sterile lemma; fruit 62. P. agrostoides. 

 stipitate ; no hairs at base of spikelets. — Moist soil, N. J. to Spikeiet x 5. 

 Ky. , and southw. 



15. P. condensum Nash. Culms stout, 0.8-1.3 m. high, sometimes geniculate 

 below ; leaves 2.5-5 dm. long, 8-12 mm. wide, flat or folded ; panicle 1-3 dm. 

 long, narrowly oblong, the densely flowered branches erect or narroidy ascending^ 

 the lower ones naked at the base ; smaller long-peduncied panicles often 

 produced from the upper nodes; spikelets 2.5 mm. long, rather turgid ; second 

 glume and sterile lemma subequal, the points usually spreading at maturity. — 

 Borders of streams and wet places, Pa. {Porter) ; Alexandria Co., Va. ; S. C. 

 and southw. 



-»-•<- Plants from stout scaly rootstocks, not conspicuously compressed at base. 



16. P. anceps Michx. Erect or ascending, 6-12 dm, high ; sheaths subcom- 

 pressed, glabrous or sparsely pilose ; blades 1.5-5 dm. long, 6-10 mm. wide, flat ; 

 panicles 2-5 dm. long, very loose and open, the slender remote branches spread- 

 ing ; small long-peduncled panicles produced from the upper nodes ; spikelets 

 more or less secund, 3.5 mm. long ; the acuminate second glume and sterile 

 lemma curved at the apex., about \ longer than the fruit lohich bears a minute 

 tuft of hairs at the apeo:. (P. rostratum Muhl.) — Moist sandy soil, R. I. to 

 Kan., and southw. July-Sept. 



****** DiCHOTOMA. — Perennials producing simple culms in the spring which 

 later branch more or less profusely, this autumnal state often strikingly 

 different in habit from the spring state ; winter rosettes of basal leaves per- 

 sistent in spring and usually different in shape from culm-leaves ; primary 

 panicles produced in spring or early summer seldom perfecting seed., the 

 secondary panicles smaller, often much reduced, the latest included in the 

 sheaths, usually cleistogamous and fruitful ; the secondary leaves usually 

 much reduced, often crowded by the dwarfing of the lateral internodes. 



•*- 1. Depauperata. — Culms tufted, slender, sparingly branching at the base, 

 simple above ; leaves long-linear, scabrous above, the basal ones shorter but 

 not forming a distinct flat rosette in the autumn; the reduced secoyidary 

 panicles, produced from short branches from the lowest nodes, more or less 

 concealed in the leaves at the base; ligule a ring of hairs about 0.5 mm. 

 long. 



17. P. depauperatum Muhl. Erect or ascending, 2-4 dm. high ; nodes 

 ascending-pubescent ; sheaths except the lowest shorter than the internodes, 

 glabrous or pilose ;, blades 6-15 cm. long, 2-5 mm. wide, often involute in dry- 

 ing ; panicles not much exceeding the leaves, 4-8 cm. long, few-flowered, the 

 rather strict remote branches ascending ; spikelets 3.2-3.8 mm. long, glabrous 

 or sparsely pubescent, strongly nerved ; first glume l-\ the length of the spike- 

 let, subacute ; second glume and sterile lemma acuminate, extending in a point 

 beyond, the fruit which is 2.3 mm. long. — Sterile woods. Me. to Minn., and 

 southw. 



18. P. perl6ngum Nash. Similar to the preceding, more strict In habit, 

 usually papillose-pilose ; blades averaging longer and narrower (sometimes 2.5 

 dm. long), pubescent on the lower surface; panicles smaller, narrow, the branches 

 nearly erect; spikelets 2.7 -S mm. long, oval, blunt, sparingly pilose, strongly 

 nerved ; first glume |-i the length of the spikeiet ; st^cond glume and sterile 

 lemma equaling the fruit at maturity, obtuse ; fruit 2.4 mm. hnni ; secondary 

 panicles usually m(n-e numerous tlian in the last, sometimes })roduced from the 

 second node. — Prairies and dry soil, Mich, and S. Dak. to Tex. 



