8 



pearance of the scales occurs, they when immature being coria- 

 ceous and showing the three nerves; but when mature being 

 very plump, apparently nerveless, and sometimes with merely an 

 acute apex in place of the awn. Occasionally some of the fruits 

 in a spike have been found v/ith bristles unbarbed. In fully 

 mature specimens this is especially apt to be true, and at the same 

 time the scabrosity of the apex of the scale becomes lost. Torrey's 

 type of var. y are immature specimens of a form of this variety with 

 scales narrower than usual, and awns longer, the plant varying 

 to^^'ard var, piunila. 



In his description of the species F. sqiiarrosa and F, hispida, 

 Elliott said very little of the characters of the perianth scales, but 

 characterized the last species principally by its slender habit and 

 hirsute sheaths. F. sqiiarrosa was described first and a drawing 

 made,* This drawing is curiously enough an excellent one of 

 the var. Jiispida, afterward described in the appendix as a species, 

 with no reference to the figure. It seems clear, therefore, that 

 Elliott, at that time at least, did not understand the true distinc- 

 tions of the two forms, basing them on characters usually present 

 but not crucial. 



New York; Junius, Seneca County (Sartwell). New Jersey 

 (Eaton, Torrey) ; Cape May (Martindale). Maryland, Salisbury 

 (Canby, Moyer). Virginia; Prince Edward County (J. D. Smith). 

 District of Columbia (Ward). South Carolina; Aiken (Ravenel), 

 Georgia (Chapman). Kentucky (Short). Florida (Buckley, 

 Chapman), Alabama (Bigelow) ; Montgomery (McCarthy). 

 Louisiana (Hale). Texas (Lindheimer No. 204, 1843, Nealley) ; 

 Hempstead (Hall No. 693, in part, 1872). 



EXPLANATION OF THE TLATK. 

 Figures uf the fruit, (achenium, bristles, and perianth-scales) of I-tdrena. All 



enlarged about ten diameters. 



I. — F. scirpoidea, Michx, 



2." — F, simplex^ Vahl. 



3. — F. sqiiarrosa^ Michx. 



4. — F, sqiiarrosa^ Alichx. var. hispida (Kll.), Chapm. 



5. — A scale of the same, as it appears when young. 



6.- — /'. sqiiarrosa^ Michx. var, hvi'lst^fa, Coville. 



^ Ell. Sk. i. pi. I. fiff. 3. 



