APRIL, 1904. PLANTS YUCATAN^; MILLSPAUGH & CHASE. 115" 



achene dark brown, 1.4x3 mm., cuneate, apex truncate, base acute; 

 in section rhomboid-lozenge shaped, the angles rounded; glabrous. 



Yucatan, on a road between Merida and Sisal, Dr. Arthur Schott, Octo- 

 ber 24, 1865, No. oij. Type in herb. Field Columbian Museum No. 40646. 



Hab. Road between Merida and Sisal, Oct. 24, 1865 Schott oij; 

 "4 .to 9 feet high, flowers pure white, clearing north of Mascab Pixoy, 

 January," Millspaugh Armour Exped. 155 (Montanoa hibisa 'folia Field 

 Col. Mus. Bot. 1:324); "climbing shrub, 20 feet high, on artificial 

 mound 8 miles southwest of Izamal, October; flowers pure white, very- 

 showy, " Gaumer 070, Chichankanab 1479, Temax 2107, 2357, Poco- 

 boch, Field Col. Mus. Cat. No. 58017, Calotmul 2108, 2358, 2jjp. 



Called by the Mayas HOMAHAK, "Trumpet vine," in reference 

 to the fruiting peduncles. This plant evidently disperses its seed 

 from the greatest height possible. The fruiting heads by their hooked 

 peduncles fasten themselves upon the neighboring trees or shrubs, and 

 from this height the achenes, free within the folded papery scales 

 which break away from the receptacle, are carried by the wind. 



ISOCARPHA R. Br. Trans. Linn. Soc., 12:110. 



Heads homogamous, discoid (rays wanting); flowers perfect, fer- 

 tile, tubular. Involucre turbinate, of dry, chaffy bracts similar to the 

 scales of the receptacle, imbricated in 2-3 series. Receptacle cylindri- 

 cal, chaffy, loosely enfolding the flowers and achenes, persistent on the 

 receptacle. Achene dorsally compressed, 4-6 angled; pappus none. 

 Herbs with small heads of whitish flowers, solitary or glomerate at the 

 end of a naked peduncle. 



Isocarpha oppositifolia (L.) R. Br. Trans. Linn. Soc., 12:110. 



Calea oppositifolia L. 



An erect, divaricately branching, pubescent herb, stem and 

 branches terete, striate; leaves 

 opposite, lanceolate, acute, sub- 

 entire, narrowed into a short 

 petiole. Inflorescence of long- 

 peduncled clusters of 1-6 (usu- 

 ally 3) heads, terminal and 

 axillary; peduncles divaricate, 

 rigid, striate, pubescent. Heads 

 8-10 mm. high, 5-6 mm. broad, 

 many flowered, subsessile. Irt- 

 volucral bracts, linear lanceolate, 

 acuminate, appressed, strongly 2 

 nerved, pubescent and granular, 

 the outer little shorter. Corolla 

 white, 5 lobed. Receptacle cyl- 

 indrical scales like the involucral 

 bracts, more abruptly acuminate ; 

 at first appressed, somewhat spreading at maturity and unfolding 

 leaving the ripe achene free. Achene black, .5-.6x 1.6 mm., obovatei 

 cuneate, 4-6 angled (usually 5); in section compressed 4-6 angled, the 

 angles sharp, the facets concave; glabrous. 



