ii4 FIELD COLUMBIAN MUSEUM BOTANY, VOL. 2. 



Achenes bilateral, styles 2-cleft: 



Plano-convex '. JUNCELLUS 



Bi-convex 



Non-tuberculate FIMBRISTYLIS 



Tuberculate, perianth, none DICHROMENA 



perianth bristles HELEOCHARIS 



Achenes trilateral, styles 3-cleft CYPERUS 



Achenes subglobose, styles 3-cleft SCLERIA 



JUNCELLUS ( Griseb.) C. B. Clarke. 



Inflorescence capitate. Fertile flowers bi-sexual; scales distich- 

 ous, lower 2 empty, persistent; spikelets many-flowered; rachilla per- 

 sistent, bristles none. Stamens 2. Style 2-cleft. Achenes plano- 

 convex, dorsally compressed. 



JUNCELLUS L^EVIGATUS (L.) C. B. Clarke in Urb. Symb. Antill. 2:21. 

 Cyperus Icevigatus Linn. Bracts 2, the lower erect, 5-10 cm. long; 



upper usually horizontal, 1-4 cm. 

 long. Heads pale-green turning 

 to chestnut, about 8 x 10 mm.; 

 congested spikelets 1-20, oblong, 

 compressed, 2 x 5-10 mm., 40- 

 fruited; scales white, more or less 

 marked with chestnut, the mid- 

 rib faint, green; broadly ovate, 

 obtuse, dorsally convex, slightly 

 longer than the achene. Achenes 

 brown, ellipsoidal, 1.3 x.y mm., 

 in section convex on the dorsum 

 and plane on the ventrum; the 

 whole surface marked by more 

 or less hexagonal ridges, includ- 

 ing nearly quadrilateral shallow pits. 



Moist banks and ditches at Guanica, Porto Rico (731). 



FIMBRISTYLIS Vahl. 



Inflorescence more or less compound-umbellate. Fertile flowers 

 bi-sexual. Scales numerous, spirally imbricated, lower short, empty. 

 Bristles none. Stamens 3. Style 2-cleft, achenes lenticular. 



Achenes lenticular non-tuberculate: 



Markings longitudinal, faint F. ferruginea 



Markings longitudinal, strong F. spadicea 



The cuts present: An enlargement of the achene, dorsal view (also lateral view in some 

 cases), a transverse section at its greatest diameter (the base of the section being the ventral side); 

 a portion of the surface magnified 25 diameters, showing the markings, and usually beneath this a 

 cross-section of the same, illustrating their prominence. The enlargements are relatively the same 

 n all the cuts. 



