PANICEiE. 139 



from widely separated localities too numerous to mention have re- 

 ceived protracted study, so far with results quite unsatisfactory. 

 It is a pity that some of tliese forms ever received distinct names. 

 For example, plants in which the nodes are clothed witli dense, 

 straiglit hairs have been called P. larhulatum Mx., often witliout 

 much regard for other peculiarities. In a similar manner, if 

 shaggy-hairy or villous, the plants have been known as P. ptihescens 

 Mx. or P. villosum Ell., or, if the leaves were smooth except 

 straight hairs on the margins, P. ciliatum Ell., or, if the culms 

 and sheaths were softly hairy, P. lanuginosiwi Ell. Plants with 

 smooth leaves varying considerably in other respects have received 

 the name of P. niticlnm Lam. If the leaves be smooth, flat, short, 

 tapering much like a wedge, the plant is P. ensifolium Baldw. In 

 a large collection there will be many specimens, each answering to 

 one and often two or more of these names ; and there will be others 

 showing various combinations of peculiarities expressed in the 

 names above given. 



Var. laxiflorum (Lam.). P. laxiflorum Lam. Encycl. 4:748 

 (1797). Leaves numerous; blades thin, lanceolate, 10-14 cm. long; 

 panicle thin. 



Dr. Watson, in Gray's Manual, Ed. 6, describes the forms or 

 varieties as: {a) commune, with simple culms erect or ascending, 

 and leaves suberect, usually pale green, {b) fasciculatiim, with clus- 

 tered leafy branches and short peduncles, a common autumn state, 

 and (c) gracile, the culms lax, very slender and elongated, with 

 rather distant spreading leaves (usually bright green), and mostly 

 long-pedunculate panicles. 



63. P. rhizophorum Fourn. Hemsl. Biol. Centr. Am. Bot., 

 3:495 (1880). 



Culms rather slender, geniculate, rooting at the lower nodes, 

 30-60 cm. high, slightly brandling, more or less puberulent. 

 Sheaths puberulent, margins pilose; ligule a mere ring; blades flat, 

 6-10 cm. long, 1.5 mm. wide, ovate-lanceolate, acuminate, inequi- 

 lateral, subcordate. Panicles mostly terminal, simple, 4-7 cm. 

 long; rays pubescent at the axils, spreading, single, the longest 

 2.5-3 cm. long, the rays bearing clusters of spikelets on the ends. 



