38 CYPERACEAE. 



4. E. canadensis L. Stems 6-15 dm. tall: leaf -blades 1-3 dm. long or more, 

 4-20 mm. wide: spike 1-3 dm. long, nodding: spikelets 3-5-flowered, the 

 empty scales awl-shaped, rigid, 3-5-nerved, 16-32 mm. long, including the 

 slender rough long awn, the flowering scales 8-14 mm. long, nearly glabrous to 

 hirsute and each bearing a slender rough awn 2-5 em. long. Susquehanna 

 valley. Eather common, on river banks. Sum. 



5. E, glabriflorus (Vasey) Scribn. & Ball. Stems 5-10 dm. tall: leaf -blades 

 1.5-3 dm. long, 6-10 mm. wide: spike erect or nodding, 1-1.5 dm: long, some- 

 times glaucous: spikelets crowded, the empty scales 11-15 mm. long, each bear- 

 ing an awn about 2 cm. long, the flowering scales 9-12 mm. long, hispidulous, 

 each bearing an awn 2-3 cm. long. Susquehanna valley. Rather rare, in 

 rich woods and thickets. Schists. Sum. 



49. HYSTBIX Moench. Usually tall grasses, with simple stems, flat leaf- 

 blades and terminal spikes. Spikelets numerous, at length spreading, 2-several- 

 flowered, usually in pairs, rarely in 3 's, sessile, the clusters alternate on opposite 

 sides of the continuous rachis, the rachilla articulated below the flowering scales. 

 Scales 2-several, the 2 lower empty, subulate, wanting in all but the lowest 

 spikelets, the flowering scales lanceolate, rigid, convolute, rounded on the back, 

 the nerves confluent into the long awn; palet somewhat shorter than the scale, 

 2-keeled. Stamens 3. Styles very short, distinct. Stigmas plumose. Grain 

 oblong, adherent to the palet when dry. 



1. H. Hystrix (L.) Millsp. Stems 6-12 dm. tall: leaf -blades 1-2.5 dm. long, 

 612 mm. wide: spike 7-18 cm. long: spikelets 8-12 mm. long, exclusive of the 

 awn, the flowering scales 8-12 mm. long, each acuminate into an awn about 

 2.5 cm. long. Rather common, on wooded banks and in rocky thickets. 

 Sum. BOTTLE-BRUSH. 



FAMILY 2. CYPERACEAE. SEDGE FAMILY. 



Grass-like or rush-like caulescent or sckpose herbs, often perennial 

 by long rootstocks. Stems or scapes (culms) slender, solid or rarely 

 hollow, triangular, quadrangular, terete or flattened. Leaves 3-ranked, 

 with closed sheaths: blades narrow. Flowers perfect or imperfect, ar- 

 ranged in spikelets, one (rarely 2) in the axil of each scale (glume, bract), 

 the spikelets solitary or clustered, 1-many-flowered. Scales 2-ranked or 

 spirally imbricate, persistent or deciduous. Perianth hypogynous, com- 

 posed of bristles, or scale-like parts, rarely calyx-like, or wanting. Androe- 

 cium of 1-3 stamens, or rarely more. Filaments slender or filiform. 

 Anthers 2-celled. Gynoecium of 2 or 3 united carpels. Ovary 1-celled. 

 Styles, or stigmas, 2 or 3, the former often more or less united. Fruit a 

 lenticular, plano-convex, or 3-angled achene. 



Spikelets with at least 1 perfect flower. 

 Spikelets perfect. 



Scales of the spikelets 2-ranked. 



Perianth present, the members bristle-like : achene 



beaked. 1. DULICHIUM. 



Perianth wanting : achene beakless. 2. CYPEKUS. 



Scales of the spikelets spirally imbricate. 



Style-base not at all or only slightly thickened, 



deciduous. 



Perianth-members conspicuously elongate. 3. BBIOPHOKUM. 



Perianth-members not conspicuously elongate. 4. SCIEPUS. 



Style-base markedly swollen, peristent as a tubercle, 



or deciduous. 

 Perianth present. 5. ELEOCHARIS. 



