FEB. 1903. PLANTS YUCATAN^E MILLSPAUGH & CHASE. 



77 



acute, submucrpnate, less than twice the length of the achene. 

 Style longer than the achene, divided to near the base. Achene 

 rusty-black, ellipsoid, .5~.6x 1.4 mm., flatly triangular in section, the 

 ventral facet somewhat concave; surface marked by faint hexagonal 

 ridges, the large interspaces occupied each by a deep circular pit with 

 a prominent lip. 



Hab. Aguada de Labcah, July 30, 1865, Schott 566; Chichan- 

 kanab, Gaumer 1288, 1289, 24.95. 



HELEOCHARIS R. Br. Prod. Fl. Nov. Holl. 1:224. 



Flowers perfect, glumes many, spirally imbricated, lower empty 

 and bracteate. Perianth of 7 bristles (in our species). Stamens 3. 

 Style 2 or 3-cleft, its swollen base persistent as a tubercle on the 

 achene. Achene biconvex or depressed trilateral. Inflorescence a 

 single terminal spike. 



Achene i mm., smooth and shining capitata. 



Achene 2.8 mm., reticulated cellulosa. 



Heleocharis capitata Torr. Ann. Lye. N. Y. 3:298. 

 Scirpus capitatus L. 



Spike light-brown, ovoid, obtuse, 3x3.5 mm.; glumes densely 

 imbricated, the lower somewhat enlarged and bract-like; fruiting 



glumes brown with green midrib, 

 broad, ellipsoidal, obtuse, twice the 

 length of the achene. Stamens twice 

 trie length of the achene. Style 2-cleft. 

 Bristles pale-ferruginous, retrorsely 

 barbed, as long as, or shorter than, the 

 achene. Achene, including the tuber- 

 cle, pyriform, .7x1 mm.; tubercle 

 white, .ix. 2 mm.; achene proper pol- 

 ished-black, in section lenticular, the 

 surfaces longitudinally marked by faint, elongated, hexagonal reticula- 

 tions, interspaces unoccupied. 



Hab. Abundant on the margins of shallower cenote"s, 12 inches 

 high, Izamal, Gaumer 424, Chichankanab, 1764; boggy soil at the 

 Caleta, island of Cozumel, Millspaugh PL Utowana 1526, borders of 

 brackish lagoon south of Progreso, 1687, Gaumer 2474. 



Heleocharis cellulosa (L.) R. Br. Prod. 225. 



Spike pale brown, cylindrical, obtuse, .4 .6x 2045 mm.; glumes 

 loosely imbricated, the lower coriaceous and appearing like a contin- 

 uation of the culm; fruiting glumes twice the length of the achene, 

 stramineous or pale green, spotted with brown, obovate, obtuse, with 



