APRIL, 1904. PLANTS YUCATAN^E MILLSPAUGH & CHASE. 119 



scales obovate, entire or notched at the summit, aristate pointed, 

 nearly as long as the disk flowers. Achene grayish black, 2.7-2.8x6-7 

 mm.; oblong-cuneate; in section 

 rhombic (or in the outer achenes 3 

 angled), the angles rounded and 

 facets slightly concave; sparsely 

 appressed-pilose; pappus of 2 slen- 

 der denticulate awns or their rudi- 

 ments, intermediate scales (in our 

 specimens) very short or obsolete, 

 caducous. 



Hab. Merida, Dec. 3, 1864, 

 Schott 68; wild and cultivated near 

 Izamal, Valdez pj {Tithonia diversi- 

 folia Field Col. Mus. Bot. 1:325); 

 "herb" 10 feet high, abundant in old 

 fields, producing its orange-yellow 

 flowers from Aug. to Sept.," Iza- 

 mal, Gaumer pp, shore of the lake, Chichankanab, /5J7, 1556, 2029, 

 Pocoboch, Field Col. Mus. Cat. No. 57855. 



Called by the Mayas TZUM, from a supposed resemblance of the 

 flower to the beard of the wild turkey. Termed CHIOPL by the Yuca- 

 lecans, who often add the cured leaves to their tobacco as an aromatic. 

 Macerated in alcohol the leaves are also used as an application to the 

 seat of pain in rheumatism, while in doses of a few drops the tincture 

 thus formed is much used as a tonic in various forms of stomach 

 disorder. 



All our Yucatan specimens have achenes devoid of pappus bristles 

 or scales at maturity; they also differ from the typical form in having 

 larger leaves and broader ligules. While absence of pappus makes 

 these plants disagree with the descriptions of Tithonia tagetiflora, and 

 even with the generic description of Tithonia, it does not seem wise 

 to establish a species or even a variety on so variable a character as 

 the pappus proves to be in this genus where it is often of 2 or 3 forms 

 in a single head. 



VIGUIERA H. B. K. Nov. Gen. et Sp., 4:224 t. 379. 



Heads heterogamous, radiate, ray flowers neutral, ligulate; disk 

 flowers perfect, fertile, tubular. Involucre depressed hemispheric of 

 dry bracts with herbaceous tips imbricated in few to several series. 

 Receptacle convex or conic, chaffy; scales convex or conduplicate, 

 embracing the achenes, persistent on the receptacle. Achene later- 

 ally compressed, more or less pilose; pappus of 2 chaffy awns, one 

 each to the dorsal and ventral angles, and several intermediate, free 

 or connate, truncate scales, persistent or deciduous. Herbs with 

 medium sized heads of yellow .flowers. 



Viguiera helianthoides H. B. K. Nov. Gen. et Sp., 4: 226, t. 379. 



A branching herb, with glabrate, striate, stem and branches, and 

 opposite and alternate, villose-petioled, lanceolate-ovate, acute or 



