226 Rhodora [Octobkb 



Similarly with P, kuachucae and 7'. implicatum, the lines between 

 these and the others are vague, Hitchcock & Chase saying in a note 

 Upon the shade-state of the former (P. kuachucae, var. sUncold), 

 "The following speeimens represent an extreme form with the upper 

 surface of the blades nearly or quite glabrous, thus approaehing P. 

 fcune.s.sccnse." Then follows an enumeration of 19 specimens to 

 which the more recent collections would surely add many more, 

 but the citation of 19 confessed intermediates is sufficient indication 

 of the weakness of the species. P. implicatum is the extreme of the 

 scries with longest pubescence on the leaves, in its best development 

 well pronounced but, to quote Hitchcock & Chase's apt phrase: 

 "More robust specimens of /'. implicatum approach 7'. huackucae" 

 In New England and eastern Canada the distinctions between the 

 two are most unsatisfactory and at best 7'. implicatum seems to be 

 of varietal rank, as Scribner, who first published it as a species in 

 IS9S, regarded it. in 1901. 



Others, like P, pacificum Hitch. & Chase, seem hardly separable 

 as species. P. pacificum has spikelets tending to be minutely larger 

 than in P. kuachucae; and its authors reason that, although " Jt most 

 nearly resembles P. kuachucae" it cannot be included in that species 

 because of "a distinct range." The type of P. kuachucae came from 

 Huachuca Mts., Arizona, and Hitchcock & Chase cite material from 

 San Bernardino Mts., California, while they allow P. pacificum to 

 occur also in the San Bernardino Mts. and to extend eastward into 

 Arizona. The ranges of the two are thus overlapping, the habit, 

 foliage and pubescence identical, and the spikelets with overlapping 

 measurements. 



The variations above discussed seem better treated as a series of 

 varieties of one wide-ranging and polymorphous species, as follows: 



Axis of panicle glabrous or at most with few apprcssed hairs: 

 leaf-blades glabrous or very sparsely pilose and glabratc 

 above, glabrous or minutely pubescent beneath; upper 

 sheaths glabrous to somewhat pilose. 



Spikelets 1.3-1.6 mm. long Var. typiewn. 



Spikelets mostly 1.6-2 mm. long Var. aeplentrionak. 



Axis of panicle spreading-pilose, at least on the lower inter- 

 nodes: leaf-blades pilose to glabrous above, commonly 

 pubescent beneath; upper sheaths mostly pilose. 

 Spikelets mostly 1.6-2.1 mm. long: leaf-blades closely 



short-pilose, sparsely long-pilose or glabrous above. Var. fasciculatum. 

 Spikelets mostly 1.8-1.5 mm. long: leaf-blades long-pilose 



above, with hairs mostly 3-6 mm. long Var. implicatum. 



