54 CYPERACEAE. 



clustered spikelets. Scales thin, 1-nerved, imbricated all around, usually 

 mucronate by the excurrent . midvein, the lower empty. "Upper flowers imper- 

 fect, the lower perfect. Perianth of 1-20 (mostly 6) upwardly or downwardly 

 barbed or scabrous bristles, wanting in some species (no. 2). Stamens com- 

 monly 3. Style 2-cleft, 2-toothed or rarely entire. Achene lenticular or 

 swollen, not 3-angled, smooth or transversely wrinkled, capped by the persistent 

 base of the style (tubercle), or in some species by the whole style. [Greek, 

 referring to the beak-like tubercle.] About 200 species, of wide geographic 

 distribution, most abundant in warm regions. Type species: Rynchospora 

 aurea Vahl. 



Style long, stout, its branches much shorter than the undivided part ; spikelets 



densely capitate. 



Heads several or numerous, panicled ; achene 1 mm. long. 1. K. cyperoides. 

 Heads only 1-6 ; achene 2.5 mm. long. 2. R. Trucyi. 



Style short, its branches mostly as long as the undivided part ; 



spikelets loosely clustered, not capitate. 

 Perianth-bristles none. 



Achene transversely wrinkled. 3. R. tennis. 



Achene reticulated. 4. JR. divergens. 



Perianth-bristles present, upwardly barbed ; achene trans- 

 versely wrinkled. 

 Achene not stipitate ; spikelets about 2 mm. long. 



Perianth-bristles much shorter than the achene or 



obsolete. 5. R. perplexa. 



Perianth-bristles as long as the achene or longer. 



Leavea 2-4 mm,, wide. 6. R. microcarpa. 



Leaves less than 1 mm. wide. 7. R. bahamensis. 



Achene stipitate; spikelets 5-7 mm. long. 8. R. marisculus. 



1. Rynchospora cyperoides (Sw.) Mart. Denkschr. Akad. Wiss. Muench. 6: 



149. 1816-17. 



Schoenus cyperoides Sw. Prodr. 19. 1788. 



Culms 8 dm. high or less, clustered, rather stout, trigonous, leaf-bearing 

 up to or beyond the middle. Leaves 3-5 mm. wide, the upper ones sometimes 

 overtopping the culm; heads subglobose, dense, usually several or numerous, 

 corymbose-paniculate, 8-12 mm. in diameter; bracts similar to the leaves, but 

 shorter; spikelets numerous, their scales 7, the 4 lower ones empty, 1 of the 

 others subtending an achene; bristles 6, upwardly hispid, longer than the 

 achene; style long, 2-cleft at the apex; achene obovoid, about 1 mm. long, 

 faintly transversely undulate; tubercle subulate, ciliate, about as long as the 

 achene. 



Swampy grounds, Great Bahama, New Providence, Eleuthera, Cat Island, Great 

 Exuma, Acklin's Island, Crooked Island, Inagua : West Indies ; tropical continental 

 America. CAPITATE BEAKED-RUSH. 



2. Rynchospora Tracyi Britton, Trans. N. Y. Acad. Sci. 11 : 84. 1892. 



Ceratoschoenus capitatus Chapm. Fl. S. U. S. 529. 1860. Not Ryncho- 

 spora capitata R. & S. 1817. 



Perennial; culms tufted, slender, glabrous, nearly terete, erect, 5-12 dm. 

 high. Leaves elongated, channelled, 4-8 mm. wide; spikelets lanceolate, 5-7 

 mm. long, densely clustered in 1-6 globose heads which are 1-2 cm. in diam- 

 eter; scales yellowish-brown, ovate, acute; bristles 6, longer than the achene, 

 upwardly barbed; achene flat, obovate, about 2.5 mm. long, ciliate, finely 

 wrinkled; style 2-cleft at the apex; tubercle subulate, setose, at least as long as 

 the achene. 



Wet soil, Great Bahama at West End ; Andros, in savanna near Staniard Creek : 

 Florida ; Cuba. TRACT'S BEAKED-RUSH. 



