APRIL, 1904. PLANTS YUCATAN^E MILLSPAUGH & CHASE. 137 



Hab. Celestun, May 13, 1865, Schott 408; Cozumel, 1885, Gaumer 

 (Oliver); "common along the coast," Progreso, Gaumer 1147, Chi- 

 chankanab 2203; "a very robust and leafy form collected in an open 

 field south of Progreso," Millspaugh PL Utowance 1652, on the beach 

 of Perez Island, Alacran Shoals 



Flaveria trinervata (Spr.) Baill. Hist. PI., 8:55. 



Oedera trinervia Spr. Bot. Gart. Halle, 63 (1800). 



A divergently branched annual, with striate stem and branches, 

 and opposite, oblong or oblanceolate, serrate, 3-nerved leaves with a 

 narrowed petiole-like base. In- 

 florescence of dense glomerules, 

 sessile in the forks or involucrate 

 at the ends of the branches. 

 Heads sessile, 4-5 mm. high, 

 i.2-j.5 mm. broaa, each with a 

 single flower, that of the outer 

 heads of the glomerule pistillate, 

 ligulate, of the inner perfect, 

 tubular. Involucre oblong of 2 

 conduplicate, oblong obtuse 

 bracts. Corolla tube hirsute, 

 ligule.5 mm long; limb of tubu- 

 lar flower campanulate, 5 lobed. 

 Receptacle minute. Achene 

 black, .7x2.3 mm., oblanceolate, 

 rounded at the summit; in section oval in outline; prominently 12 

 ribbed, glabrous. 



Hab. Downs of Progreso, Dec. 1865, Schott 973 {Flaveria repanda 

 Lag. Field Col. Mus. Bot. 1:395); along the coast, Progreso and Me- 

 rida, Gaumer 1147 in part. (Flaveria repanda Lag. Ibid.}, Silam 1246, 

 herb 2 feet high, common, Chihankanab /J77, 1483; ditches near 

 Progreso, Millspaugh PL Utowance 1653, along the railroad south of 

 the lagoon crossing, Progreso, 1699, 1731 {Brottroa trinervata Pers. 

 Ibid. 2 1109). 



HELENIUM L. Sp. PL, 886. 



Heads heterogamous, radiate, ray flowers pistillate and fertile or 

 neutral, ligulate; disk flowers perfect, fertile, tubular. Involucre 

 broad and short of linear bracts in i or 2 series, spreading or reflexed. 

 Receptacle convex to subglobose, naked. Achene not compressed, 

 turbinate, ribbed; pappus of 5 to 8, aristate or dentate scales. Herbs 

 with punctate, bitter leaves and showy heads of yellow flowers. 



Pappus of aristate scales 2-2.5 mm. long 

 Pappus of ecostate scales 3 mm. long 



tenuifolium. 

 quadriden tatum. 



Helenium tenuifolium Nutt. Jour. Acad. Phila., 7:66. 



An erect, branching annual with sulcate, glabrous, resin dotted 

 stem, peduncles and branches, and crowded, alternate, sessile, linear 

 punctate leaves. Inflorescence of solitary long-peduncled heads, 



