BULLETIN 



OF THE 





TORREY BOTANICAL CLUB 



Vol. XVI 1.] New York, January 15, 1890. [No. I 



Revision of the United States species of the genus Fuirena, 



Bv Frkderick V. COVILLE. 



Plate XCVIII. 



The various forms of Fuircna grouped under the name 

 F, squarivsa, Mx., show much variation in both external 

 and internal characters. The external variations are confined 

 commonly to those of size, hairiness, and inflorescence. The 

 height varies from 5 cm, to 90 cm. 



Hairiness of the leaves, stem, and sheaths seemed iX first to 

 form the basis of good varietal distinctions, but a careful com- 

 parison of specimens shows that there is sometimes wide varia- 

 tion within the limits of a variety. I am inclined to believe that 

 these differences may be due largely to individual environment. 

 They certainly are not in all cases co-ordinate with other well 

 defined characters. 



The width of the leaves varies, in the specimens that I have 

 examined, from i mm. to 7 mm. according to the size of the 

 plant. The inflorescence varies from a single spike to one or a 

 few several-spiked heads. The internal variations noted are in 

 the length of the stipe of the achenium, the length and rough- 

 ness of the bristles, and several variations in the perianth-scales. 



The achenium may have a stipe equal to its own length, or 

 may be nearly sessile. The bristles are sometimes shorter than 

 the stipe of the achenium, when they are usually smooth ; or 

 they may equal the achenium, or even greatly exceed it. In 

 these latter cases they are retrorsely barbed. 



The perianth scales have a stalk reaching to about the base 

 or middle of the achenium, and there expanding into a blade 

 (usually referred to as the scale). The scale varies in form from 

 narrowly oblong with acute apex and base, to broadly oblong 

 with obtuse apex and base, and deltoid ovate with acute apex 

 and cordate or truncate base. It varies also much in thickness, 



