194 Rhodora [August 



** P. DKPAri'KKAnM, var. psilophyllum, forma cryptostachys, 

 n. f'., paniculis omnino reductis basilaribus, spiculis 1-4. — Nova 

 Scotia: dryish open sandy plains, Middleton, July 20, 1920, Femuld 

 Pra.se & Long, no. 19,709 (type in Gray Herb.); dry sandy thickets 

 and borders of woods, Middleton, July 21, Ferncdd & Pease, no. 

 19,770. See p. 138. 



Var. psilophyllum is the common plant with sheaths sparsely pilose 

 or quite glabrous. This extreme and the plant with copiously pilose 

 sheaths were both included by Muhlenberg in his P. depauperatum 

 but by Hitchcock & Chase "a specimen with pilose sheaths . 

 has been chosen as the type." Whereas var. psilophyllum is the 

 dominant plant of the North, the more pilose extreme is commoner 

 in the southern and central states. Tims, of the ll'.\ sheets of speci- 

 mens examined from Nova Scotia, Quebec and New England, 152 

 arc var. psilophyllum and only 21 the plant with copiously pilose 

 sheaths. Conversely, all the material examined from North Caro- 

 lina, and Georgia to Arkansas, Missouri and Illinois is typical /'. 

 depauperatum. 1 



Recently Mr. P. T. Hubbard (Rhodora, xiv. 169) has taken up 



the name P. striatum Pursh (1814) to displace P. depauperatum Mnhl. 

 (1817) in spite of the earlier P. striatum H. Br. (1810); Hubbard cit- 

 ing as a basis for his change Articles ^7 and 50 of the International 

 Rules. But the application of Art. M (rejecting names published 

 without diagnoses or merely cited in synonymy) is not apparent, for 

 Robert Brown published /'. striatum as a valid species with careful 

 description. Art. 50 was applied by Hubbard to the case of P. stric- 

 t n in. Pursh through an obvious misapprehension, for, although P. 

 striatum R. Br. is treated in Index Kewensis as a synonym of P. 

 marginatum, it is not so treated by those who know the plants; 

 Bentham, P. M. Bailey and other students of the Australian flora 

 all maintaining it as at least a good variety, which rests directly 



1 In its greater abundance northward /'. depauperatum, var. psilophyllum is com- 

 parable with 



P. linbarifolium Scribn., var. Werneri (Scribn.), n. comb. P. Werneri 

 Scribn. in Britton & Brown, 111. Fl. iii. 501, fig. 268b (1898). 



Typical P. linearifolium has copiously pilose sheaths, var. Werneri gla- 

 brous sheaths. The very minute difference in spikelets relied upon by 

 Hitchcock & ('base is very inconstant and wholly unsatisfactory and the 

 only usable distinction is in the sheath. Of 103 sheets examined from Que- 

 bec and northern and central New England 7(i are var. Werneri, 27 the typ- 

 ical form of P. linearifolium. Conversely, of 28 sheets examined from Mis- 

 souri 2(> are typical /'. linearifolium and only 2 var. Werneri. 



