1905] Fernald, North American Species of Eriophorum 131 
The removal of the tall Eriophorum cyperinum and its numerous 
allies from the genus leaves what is in many ways a natural group ; 
but as treated by Linnaeus in the first edition of the Species 
Plantarum and as ordinarily accepted, Eriophorum contains one 
species, Æ. alpinum, which, like the Wool Grasses, still leaves the 
genus unsatisfactorily distinguished from Scirpus. With the excep- 
tion of this single species, Eriophorum alpinum, the members of the 
genus (with Æ. cyperinum and its allies removed to Scirpus) have 
many characteristics in common which define the group as a well 
marked genus. All have the membranous scales of the spikelets with 
spreading or loosely ascending tips, and the perianth of many slender 
ligulate bristles;! and in the monocephalous species, Æ. vaginatum, 
&c., with which Æ. alpinum has been associated, the culms are 
usually invested with loose often somewhat inflated membranous- 
tipped sheaths; the spikelets are large, of very numerous membra- 
nous or scarious spreading or spreading-ascending scales, several of 
the lower empty, and the outermost enlarged, 3-several-nerved and 
persistent. 
Eriophorum alpinum, however, which has been very generally 
treated as a close ally of Æ. vaginatum, &c., but which, with Scirpus 
cyperinus and S. lineatus, was made by Persoon the basis of another 
genus, Zrichophorum? has characteristics which separate it very 
clearly from Lriophorum. The sheaths of Eriophorum alpinum, con- 
fined chiefly to the base of the plant, are close and firm; the 
spikelets subulate-ovoid, about 5 mm. long, of few incurved-ascending 
chartaceous scales, the outermost of which is caducous and has its 
strong green costa prolonged into a blunt mucro; and the ligulate 
bristles are only 6 in number. In all these characteristics the plant 
is so closely similar to the boreal Scirpus caespitosus, L., and Scirpus 
alpinus, Schleicher, that more than one student of the group has com- 
mented upon the fact. Thus, in 1836, Torrey remarked that “This 
Eriophorum differs from all the other single-spiked species of the 
genus in the rigid scales of the spike, and in the definite crisped 
bristles ”;3 and by others, as recently, in a very detailed discussion 
of the anatomical structure of the stems of the plants which have 
1 By some authors spoken of as ligulate segments of 6 deeply cleft bristles (see 
Clarke in Hook. Fl. Br. Ind. vi. 663). , 
2 Persoon, Syn. i. 69 (1805). 
3 Torr. Ann. Lyc. Nat. Hist. N. Y. iii. 335 (1836). 
