34 



CYPERACEAE. 



VOL. I. 



2. Hemicarpha aristulata (Coville) Smyth. 

 Avvned Hemicarpha. Fig. 837. 



H. micrantha aristulata Coville, Bull. Torr. Club 21 : 



36. 1894. 

 H. aristulata Smyth, Trans. Kans. Acad. Sci. 16 : 163. 



1899. 

 H. intermedia Piper; Piper & Beattie, Fl. Pal. Reg. 36: 



1901. 



Similar to the preceding species; culms 8' high or 

 less, longer than the setaceous leaves ; invqlucral 

 leaves 1-3, sometimes nearly i' long. Spikelets 

 ovoid, 2"-4" long; scales rhombic-obovate, brown, 

 rather abruptly contracted into a subulate spreading 

 or somewhat recurved awn about as long as the 

 body; inner scale larger than that of H. micrantha; 

 style short ; achene narrowly obovate, black. 



Wet, sandy soil, Kansas to Wyoming, Colorado and 

 Texas ; California and Washington. 



H. OCCidentalis A. Gray, a species of California and 

 Oregon, with larger subglobose heads and lanceolate 

 scales, is erroneously recorded from western Ontario. 



ii. DULICHIUM L. C. Richard; Pers. Syn. i: 65. 1805. 

 A tall perennial sedge, with terete hollow jointed culms, leafy to the top, the lower 

 leaves reduced to sheaths. Spikes axillary, peduncled, simple or compound. Spikelets 

 2-ranked, linear, many-flowered, breaking up into i-fruited joints at maturity. Scales 

 2- ranked, carinate, conduplicate, decurrent on the joint below. Flowers perfect. Perianth 

 of 6-9 retrorsely barbed bristles. Stamens 3. Styk 2-cleft at the summit, persistent as a 

 linear-oblong beak on the summit of the achene. [Name said to be from Dulcichimum, a 

 Latin name for some sedge.] A monotypic genus. 



i. Dulichium arundinaceum (L.) Britton. 

 Dulichium. Fig. 838. 



Cyperus arundinaceus L. Sp. PI. 44. 1753. 

 Cyperus spathaceus L. Syst. Ed. 12, 2: 735. 1767. 

 Diillchium spathaceum Pers. Syn. i : 65. 1805. 

 Dulichium arundinaceum Britton, Bull. Torr. Club 

 21 : 29. 1894. 



Culm stout, i-3 tall, erect. Leaves numerous, 

 3-ranked, flat, i'-3' long, 2" -4" wide, spreading 

 or ascending, the lower sheaths bladeless, brown 

 toward their summits. Spikes shorter than or 

 the uppermost exceeding the leaves ; peduncles 

 2"-i2" long; Spikelets narrowly linear, spreading, 

 6"-i2" long, about i" wide, 6-i2-flowered ; scales 

 lanceolate, acuminate, strongly several-nerved, 

 appressed, brownish; bristles of the perianth 

 rigid, longer than the achene; style long-exserted, 

 persistent. 



In wet places, Newfoundland to Ontario, Minne- 

 sota, Washington, Florida and Texas. Also in Costa 

 Rica. Aug.-Oct. 



12. DICHROMENA Michx. Fl. Bor. Am. i: 37. 1803. 



Leafy-stemmed sedges, perennial by rootstocks, the spikelets crowded in a terminal head 

 involucrate by the upper leaves, which are often white at the base. Spikelets compressed, 

 several-many-flowered. Scales spirally imbricated all around, several of them with imper- 

 fect flowers, or empty. Perianth none. Stamens 3. Style 2-cleft, its branches subulate. 

 Achene lenticular, transversely rugose, -crowned with the broad persistent base of the style 

 (tubercle). [Greek, alluding to the two-colored involucral leaves.] 



About 20 species, natives of America. Besides the following, 2 others occur in the southwestern 

 United States. Type species': Dichromena leucocephala Michx. 



Leaves of the involucre linear; tubercle truncate at the base. i. D. colorata. 



Leaves of the involucre lanceolate, long-acuminate ; tubercle decurrent on the edges of the achene. 



2. D. latifolia. 



