1921] Fernald, — Expedition to Nova Scotia 



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P. tcnucsscrn.sc are placed in the section Lanuginosa with "Sheaths 

 strongly pubescent." The spikclct-nieasurements as given by them 

 are: P. Lindheimeri, 1.4-1.6 mm. long; P. huachucae 1.6-1.8 mm. 

 and P. tennesseensc, 1.6-1.7 mm. The last, although placed in a 

 group with "Sheaths strongly pubescent," is described as having 

 "sheaths . . . rarely nearly glabrous," while in the "glabrous" 

 /\ Lindheimeri "sometimes the pubescence extends nearly to the 

 summit. These more pubescent specimens . . . resemble less 

 pubescent specimens of P. tennesseensc but can be distinguished by 

 the smaller spikelets." If the difference between the extremes of 

 the spikelets were positive, the latter assurance would carry convic- 

 tion; but when, measuring the spikelets of specimens labelled (and 

 often cited) by Hitchcock & Chase as P. tennesseensc, it is found 

 that several sheets (Framingham, Mass., E. C. Smith; Providence, 

 \{. 1., Collins; East Hartford, Conn., Dru/c/s; Washington, 1). C, 

 Steele; Monteer, Mo., Bush; etc.) shows mature spikelets only 1.4- 

 1.6 mm. long, while this minimum is exhibited by a sheet specially 

 collected by Mrs. Chase and distributed to show true P. tennesseense 

 (Am. Gr. Nat. Herb. no. 127); — when we find that P. tenncsseense 

 may have spikelets as small as in P. Lindheimeri, the effort to sepa- 

 rate the two as species becomes futile. This futility is further em- 

 phasized by the plant of Yarmouth County, Nova Scotia, in habit 

 so closely similar to the type-number of P. Lindheimeri as at first 

 to seem identical with it, but with spikelets even larger than in /'. 

 tennesseensc, 1.8-2 mm. long. 



Panicum tennesseensc, itself, as treated by Hitchcock & Chase, 

 consists of two rather definite trends. Of the material in the Gray 

 Herbarium and the herbarium of the New England Botanical Club 

 so named by them f8 sheets have panicles with the lower internodes 

 pilose as in 7\ huachucae, var. silvicola, which likewise has spikelets 

 of the same size; while 25 have the axis of the panicle glabrous as in 

 /'. Lindheimeri. Some sheets of the latter plant from the St. John 

 valley in northern Maine have been labeled by them P. Lindheimeri; 

 others of the same plant, P. tennesseensc. One sheet from Massa- 

 chusetts (Hubbard, no. 205) with the characteristic panicle, long 

 spikelets and pilose axis of P. languidum was determined by Mrs. 

 Chase in 1911 as the latter species, but, naturally enough, in 1912 

 she changed the determination to P. tennesseensc; naturally enough 

 because, as the preceding discussion indicates, those species are 

 merely phases of one polymorphous species, P. Lindheimeri. 



