56 TRIANDRIA. MOXOGYNIA. 



been considered a Scirpiis (M\chaux)y by many a Cypertis 

 (Willdenow), and Yahl has decribed it as a Schamis; it 

 certainly approaches the g-enus Cyperus, but is distin- 

 guished from it by the presence of the g-erminal fila- 

 ments, and its subulate glumes. In habit it very widely 

 recedes from Scirpiis and .S'cAa?«w5, and all the glumes, be- 

 sides their very peculiar form and mode of aggregation, 

 are uniformly fertile. 



Species, i. D. spathaceum. 2. Canadense. (This genu-s 

 is peculiar to the United States.) 



54. TRICHOPHORUM. Persoon. 



Spikelets nearly ovate; Calix scales imbri- 

 cated on all sides. Corolla 0. Germinal setse 

 (invohicellum) capillary, mostly 6, in the ripen- 

 ing seed, growing out very long. 



Culm triquetrous, leafy, terminated by a paniculate 

 umbell; or naked, with a single spike; involucellum of the 

 seed capillary and definitely parted, (setje about 6) not 

 woolly and indefinite as in Ei'iophoruin, to which genus 

 the T. alpiiiKm and T- Hmhonianum have hitherto been 

 referred. The T. ajperinum has a very near affinity to 

 the genus Scirpus, where it was placed by Michaux, and 

 from its great dissimilarity of habit with the Enophorum 

 <tlpima7i,no\y referred to Trichophonwi by Persoon, we are 

 obliged to consider the present genus as very arbitrary 

 and artificial. All the species of Trichophontm, naturally 

 belong to tlie genus Scirpus, and there is no line of sepa- 

 ration, except we are to consider the elongation of the se- 

 tr.inal filaments QV involucellum, as a solitary character, suf- 

 ficient to constitute a genus: for the number of the setae, 

 6, so carefully inserted in the generic character, is the 

 prevailing number in the genus Scirpus. (Mr. Pursh adds 

 setis 6-9 ) 



Species. 1. T- cyperiimm. 2. Hudsonianum, (nesirlyaX- 

 lled to the Enophorum alpinum — only 3 or 4 inches high, 

 with a solitary spike.) 



Considered as a genus, the most remarkable of its spe- 

 cies is the T. cyperinum, confined to North America, but 

 extending from Canada to Florida; the T- Huilsonianiimt 

 if merely a variety of the T. alpinum, is common to the 

 sub-alpine regions of Europe, and North America. 



55. ERIOPHORUM. (Cotton-grass.) 



Scales of the calix chaffy, imbricated on all 

 sides in a spike. Corolla 0. Seed surrounded 



