IOO 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



CONYZA Less. Syn. Comp., p. 203. 



Heads heterogamous, discoid; several rows of marginal flowers 

 pistillate, fertile, the corolla reduced to a filiform tube, destitute of 

 ligule; central flowers perfect, fertile, very slender tubular. Involucre 

 campanulate, of narrow bracts imbricated in few to several series, the 

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

 laterally compressed; pappus of i series of capillary bristles. Herbs 

 with rather small corymbose heads. 



Conyza lyrata H. B. K. Nov. Gen. et Sp., 4:55. 



An ascending or erect, branching viscous herb with subangled 

 glandular-pilose or puberulent stem and branches and alternate, sessile, 

 obovate, sinuate-lyrate, dentate, brown farinose leaves. Inflorescence 

 of cymose clusters of few to many heads terminating leafy branches; 



branchlets and pedicels densely 

 brown farinose and sparsely pu- 

 bescent with soft spreading 

 white hairs. Heads 6-7 mm. 

 high, 12-14 rnm. broad, many 

 flowered. Involucral bracts 

 loosely imbricated in 3 series, 

 lanceolate-linear, acuminate, the 

 outer densely brown farinose, the 

 inner glabrous except a farinose 

 median line, ciliate at the sum- 

 mit, exceeding the pappus. 

 Marginal corollas white, central 

 yellowish Receptacle subcon- 

 vex. Achene chestnut, .2x1 

 mm., oblong, rounded at the 

 base; in section oblong; nerve- 

 less, villous; pappus bristles 10-15, brownish white, nearly smooth 

 4-5 mm. long. 



Hab. "Herb, 4 feet high, common in towns, flowers white," 

 Izamal, Gaumer fij, Chichankanab 1453, Pocoboch 2406. 



BACCHARIS L. Sp. PL, 860. 



Heads dioecious, discoid, many flowered, flowers of fertile heads 

 pistillate, of sterile heads perfect. Involucre campanulate, of many 

 bracts imbricated in several series, outer gradually shorter. Recep- 

 tacle naked, plane. Achene laterally compressed, ribbed ; pappus of 

 numerous capillary bristles. Dioecious shrubs; with small panicled 

 or corymbose heads. 



Baccharis halimifolia L. Sp. PI., 860. 



A freely branching, glabrate shrub with striate stem and angled 

 branches, and thickish alternate, obovate to oblong leaves with cune- 

 ate base attenuate into a petiole, 3-9 toothed, those of the flowering 

 branches lanceolate, mostly entire. Inflorescence of axillary and 

 terminal peduncled clusters of 1-5 subsessile heads; branches and 



