82 PANIC'ACI'LE. 



eiitiroly deficient iu tlie section Diyitaria ; consequently several 

 species have been referred bv some botanists to one genns and by 

 otliers to tlie other. Tliese ambiguous species aj^pear to be best 

 jilaced in Poniofm. 



All the true Paspnhi have the spikelets sessile or nearly so. in 

 two to four rows along tlie lower or outer side of the rachis or 

 simple branches of the panicle. Scairely five species can be regarded 

 as belonging exclusively to tlie Old World. General ^Funro luid 

 nearly completed a moiiogra])h of the genus, leaving des('rii)tions of 

 138 species. lie and Dr. Ik'ntham agreed ])erf('ct]y in not making 

 species to show all slight variations, corresponding to what many 

 local European b(ttanists describe as critical species. 



Trillins subdivided the genns, chiefly according to the size of 

 the s[)ikelets. 



Hentham and Hooker adojited three siictions, founded on Xces's 

 — Kiipaxpalum. Cahrcnt. and JnafttrojiJnift, subdividing the tirst and 

 mucli tlie largest into four groups — Anaclnjris, Opistliion, Psendo- 

 ceri\si((. and Ccn'sia. 



J>/(ic/ii/n's\nn purely artificial one, characterized solely b^ having 

 only a single empty glume below the ilowering one. It was first 

 ]iro])osed as a genus l)y Nees for Pd.ynilinn vuilacophyUum Trin. 

 Opixlliio)) was j)ropos(.Hl by Doell as a section of PaKjudum, 

 but Hentham and Hooker use it as a name for a group. It in- 

 cludes all the tyjiical PaspaJu with two lower emiity glumes, and 

 tile rachis of the spikes not dilated. The species are numerous and 

 varied. Pytexdorcresin is the name of the grouj) of species in Mhich 

 th(> rachis of the spikes is more or less dilated and concave, but 

 green and herbaceous throughout, and the spikelets are small and 

 glabrous or nearly so. The species are few. incluuing P. rcpens 

 IJerg. and its allies. Ccrcsin is the name proposed for a genus by 

 Persoon. Here the dilated rachis of the spike is bordered by a 

 colored or smooth membranous margin and the half-enclosed 

 si)ikelets arc larger than in Psi'in/orcrcsid and densily ciliate. 

 Cahrera. the second section of f^fsalion, contains a single species, 

 P. anretdii II.B.K., forming Fiagasca's genus Cahvcra. In thi.^ 

 the direction of the spikelets is nearly that of .l>/rt.s//'6»/^////.s'; but 



