n6 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. 2. 



achene lenticular, tuberculate. Inflor- 



Stamens 3. Style 2-cleft; 

 escence a terminal spike. 



HELEOCHARIS CAPITATA (L.) R. Br. Prod. 225. 



Scirpus capitatus Linn. 



Spike light-brown, ovoid, obtuse, 3x3.5 

 imbricated, the lower somewhat 

 enlarged and bract-like; fruiting 

 scales brown with green midrib, 

 broad, ellipsoidal, obtuse, twice 

 the length of the achene. Sta- 

 mens twice the length of the 

 achene. Bristles pale - ferru- 

 gineous, retrorsely barbed, as 

 long as, or shorter than, the 

 achene. Achene, including the 

 tubercle, pyriform, .7x1 mm.; 

 tubercle white, . i x .2 mm.; 

 achene proper polished-black, in 

 section lenticular, the surfaces longitudinally marked 

 gated, hexagonal reticulations, interspaces unoccupied 



Boggy spot in a field at Catafio, Porto Rico (175); 

 Caleta Cozumel (1526): borders of a brackish lagoon 

 greso, Yucatan (1687). 



mm. ; scales densely 



by faint, elon- 



wet soil at the 

 south of Pro- 



DICHROMENA Vahl. 



Inflorescence in a terminal head subtended by long leaf-like 

 bracts. Fertile flowers bi-sexual; scales numerous, spirally imbricated, 

 the lower and upper empty or infertile; spikelets few-fruited; bristles 

 none. Stamens 2 or 3. Style long, 2-cleft, achene lenticular or 

 appearing elliptical tuberculate: 



Achenes bi-convex, tuberculate: 



Ridges few, transverse, smooth D. pubera 



cellular, large . . . . , ' D. colorata 



small D. radicans 



DICFTROMENA PUBERA Vahl. Enum. 2:241. 

 Schcenus pubescens H. B. K. 

 Dichromena nervosa Britton, on page 30. 



Bracts six, 3-9 cm. long, deflexed spreading, softly pubescent, cili- 



ate and white on the upper sur- 

 face at the base. Heads pale- 

 cinnamon, subglobose, 10 - 14 

 mm. 'wide, composed of 5-8 

 spikelets; spikelets narrowly 

 ovoid, 8x3 mm., 3 - fruited; 

 scales ovate, subacute, more than 

 twice the length of the achene. 

 Stamens 2. Achenes bronze- 

 brown, the beak excluded de- 

 pressed-globose, 1.3x1.4 mm.; 



beak dark-brown, sharply conical, decurrent at the base, .6 mm. high. 



