9 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



ALOMIA H. B. K. Nov. Gen. et Sp., 4:i5 r > *. 354- 



Heads homogamous, discoid, flowers perfect, fertile-tubular. 

 Involucre hemispheric, of herbaceous bracts, imbricated in 2-3 series, 

 unequal. Receptacle naked, convex. Achene 5 sided, not compressed; 

 pappus none or a minute crown. Herbs, with small paniculate heads. 



Alomia ageratoides H. B. K. Nov. Gen. et. Sp., ^S 1 , t. 354. 



An erect or ascending, diffusely branching annual, with terete, 

 striate, pubescent or glabrate stem and branches, and opposite, long- 



petioled, ovate, crenate, nearly 

 glabrate leaves. Inflorescence a 

 cymose panicle of 3-10 heads on 

 a slender peduncle. Heads 

 many flowered, 6-7 mm. high, as 

 broad or broader, on striate, 

 finely canescent, bracteate, slen- 

 der pedicels. Involucral bracts 

 in 2 series, lanceolate, acute, 

 having 2 strong nerves and thin 

 ciliolate margins. Corolla 5 

 lobed, white with light purple 

 lobes. Receptacle faveolate. 

 Achene, except the white callus, 

 black and shining, .4-. 5 x 1.6-1.7 

 mm., oblong, little narrowed at 

 the base, apex truncate; in sec- 

 tion depressed-pentagonal, strongly 5 nerved, a few scattered hairs on 

 the nerves, otherwise glabrous; pappus reduced to a minute crown. 



Hab. Tekanto and Tunkas, Feb. and March, 1890, Stone ipo, 

 238 (in Herb. Acad. Sci. Phila. ) ; Cozumel Island at San Miguel, Mills- 

 paugh PI, Utowance 1492, and east shore, 1603. 5 ^ 



AGERATUM L. Sp. PL, 839. 



Heads homogamous, discoid, flowers perfect, fertile, tubular. 

 Invplucre wide campanulate, of herbaceous bracts imbricated in 2-3 

 series, subequal. Receptacle naked, plane or convex. Achene 5 sided, 

 not compressed; pappus i-serial, of aristate scales. Herbs, with 

 small paniculate heads. 



Ageratum intermedium Hemsl. Biol. Cent. Am., Supplement p. 102. 

 An erect or ascending, branching annual, with terete, sparsely 

 white-pilose stem and branches, and opposite, long-petioled, 

 ovate, acute, crenate-dentate, sparsely pilose leaves. Inflo- 

 rescence loosely cymose-panicled, branches and pedicels slender, 

 striate, bracteate. Heads many flowered, 5 mm. high, 8-10 mm. 

 broad. Involucral bracts in 2 series, nearly equal, oblong, acuminate, 

 having 2 strong nerves and hyaline margins. Corolla light purple, 

 5 lobed. Receptacle convex. Achene (except the white callus) 

 black, .4X 1.5-1.7 mm., oblong, little narrowed at the base, apex trun- 



