494 CYPERACE^E. (SEDGE FAMILY.) 



16. C. Grayii, Torr. Culm thread-form, wiry (6' - 12' high) ; leaves nearly 

 bristle-shaped, channelled ; umbel simple, 4 - Grayed; spikes 5 - 10 in a loose head, 

 spreading, 5- 7-flowered, the joints of the axis winged; scales rather obtuse, green- 

 ish-chestnut-color ; achenium obovate, minutely pointed. Barren sandy soil, 

 Rhode Island to New Jersey, near the coast. Aug. (Approaches the next.) 



17. C. filiculmis, Vahl. Culm slender, wiry, often reclined (8' -15' 

 high) ; leaves linear (1" - 2" wide) ; spikes numerous and clustered in one sessile dense 

 head, or in I -3 additional looser heads on spreading rays, 6 - 10-flowered ; joints oj 

 the axis naked ; scales blunt, greenish; achenium obovate, short-pointed. (C. ina- 

 riscoides, Ell.) Dry sterile soil; common, especially southward. Aug. 



4. MARf SCUS, Vahl. Style 3-cleft : the achenium triangular : stamens 3 : 

 spikes 1 -few-flowered, scarcely flattened ; the 2 lower scales short and empty : oth- 

 erwise as in 3. 



18. C. OVUlariS, Torr. Smooth; culm sharply triangular (6' -12' high) ; 

 umbel 1 - 6-rayed ; spikes in globular dense heads, 2 - ^-flowered, short and thick : 

 joints of the axis winged ; scales ovate, blunt, greenish ; achenium obovoid. 1J. 

 (Kyllingia, Michx.) Sandy soil, S. New York to Virginia, and south ward. 

 Aug. - Oct. Heads barely ' in diameter, of 50 - 100 spikes. 



19. C. retro fractllS, Torr. Culm minutely downy like the leaves, rough 

 on the obtusish angles ( 1 - 3 high ) ; umbel many-rayed ; spikes slender, awl- 

 snaped, very numerous in obovate or oblong heads terminating the elongated 

 rays, soon reflexed, 1 - 2-flowered in the middle ; scales usually 4 or 5, the two 

 lowest ovate and empty, the fertile lanceolate, the uppermost involute-awl-shaped ; 

 achenium linear. 1| (Scirpus retrofractus, L.) Sandy fields, New Jersey to 

 Virginia, and southward. Aug. Spikes ' long, 50- 100 in a head, greenish. 



2. KYLLINGIA, L. KYLLINGIA. 



Spikes of 3-4 two-ranked scales, 1 -1^-flowered; the 2 lower scales minute 

 and empty, as in Cyperus 4 , otherwise as in Cyperus 1 (viz. style 2-cleft ; 

 achenium lenticular) : but the numerous spikes densely aggregated in solitary 

 or triple sessile heads. Involucre about 3-leaved. (Named after Kylling, a 

 Danish botanist.) 



I. K. ]>iunila, Michx. Head globular or 3-lobed, whitish-green (4" 

 broad) ; spikes strictly 1-flowered ; upper scales ovate, pointed, rough on- the 

 keel ; stamens 2 ; leaves linear. Low grounds, Ohio to Illinois, and southward. 

 Aug. Culms 2' - 9' high. 



3. DUIjiCHIIJlfEy Richard. DULICHIUM. 



Spikes many- (6 - 10-) flowered, linear, flattened, sessile in 2 ranks on axillary 

 solitary peduncles emerging from the sheaths of the leaves. Scales 2-ranked, 

 lanceolate. Perianth of 6 - 9 downwardly barbed bristles. Stamens 3. Style 

 2-cleft above. Achenium flattened, linear-oblong, beaked with the long persist- 

 ent style. A perennial herb, with a terete simple culm (l-2 high), jointed 

 and leafy to the summit; the leaves short and flat, linear, 3-ranked. (The name 

 of a Greek island ; its application unexplained.) 



