APRIL, 1904. PLANTS YUCATAN^: MILLSPAUGH & CHASE. 



97 



Hab. "Vine 15 feet, flowers white, common at Xcholac, Jan. to 

 Feb.," Gaumer 443 (Mikania scandens Willd. Field Col. Mus. Bot. 2:324). 



In Yucatan and West Indian specimens the pappus is usually 

 more or less pinkish, while in those from the United States the pappus 

 is white. 



COLEOSANTHUS Cass. Diet, 10:36. 



Heads homogamous, discoid, flowers perfect, fertile. Involucre 

 campanulate, of narrow, striate bracts, imbricated in 2 series. Recep- 

 tacle naked, plane or convex. Achene 10 ribbed, pappus 'of many 

 slender bristles in i series. Herbs or shrubs, heads few to many 

 flowered, in panicles or cymes. 



Coleosanthus diffusus (Vahl) Kuntze Rev. Gen. PI., 1:328. 



Eupatorium diffusum Vahl. 



An erect annual, branching above, with subangled brown-puberu- 

 lent stem and branches, and opposite, petioled, rhombic-ovate or sub- 

 cordate , acuminate, dentate 

 leaves. Inflorescence an elon- 

 gated, diffuse, cymose panicle: 

 the main axis and lower part of 

 branches puberulent, secondary 

 branches and pedicels glabrate, 

 slender. Heads 7-12 flowered, 

 7 mm. high 8-10 mm. broad. 

 Involucral bracts in 2 series, 

 loosely spreading, narrowly lan- 

 ceolate, acuminate, strongly 

 nerved, the outer ciliolate, the 

 inner glabrate. Corolla white. 

 Receptacle plane. Achene dull 

 black, .5x1.9-2 mm. subcom- 

 pressed cylindrical, little nar- 

 rowed at base, apex truncate; in section, elliptical; 10 ribbed, mi- 

 nutely hirsute; pappus bristles white, nearly smooth, 4 mm. long. 



Hab. "Herb 10 feet high, uncommon in fields and brushlands 

 near Izamal, flowering from December to March," Gaumer 1080 

 (Brickellta diffusa A. Gray Field Col. Mus. Bot. 1-394). 



GRINDELIA Willd. Ges.' Nat. Fr. Berl. Mag., 1807, p. 259. 



Heads heterogamous, radiate; rays pistillate fertile, ligulate; 

 disc flowers perfect, fertile or sterile, tubular. Involucre depressed 

 hemispheric, of many coriaceous bracts, imbricated in many series, the 

 outer gradually shorter. Receptacle naked, plane or convex. Achene 

 laterally compressed, hard, 4-5 ribbed; pappus of 2-8 deciduous awns 

 or bristles. Resinous herbs, with solitary heads of yellow flowers. 



Grindelia nana Nutt. Trans. Am. Phil. Soc., N. S. 7:314. 



A slender, erect annual, branching above, with smooth, striate 



t 



