n8 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



4 angled; pappus of 2 chaffy awns one each to the dorsal and ventral 

 angles, and several intermediate scales, persistent or deciduous, or 

 pappus nearly obsolete. Robust annuals with large showy heads of 

 yellow flowers. 



Pappus persistent 

 Pappus deciduous 



diversifolia 

 tagetiflora 



Tithonia diversifolia (Hemsl.) A. Gray Proc. Am. Acad., 19:5. 

 Mirasolia diversifolia Hemsley. 



An erect, branching, annual with alternate wing-petioled, ample, 



acutely 3-5 lobed, serrate, scab- 

 rous leaves. Inflorescence of 

 solitary, terminal and axillary 

 heads; peduncles clavate, fistular 

 toward the summit, striate, glab- 

 rous. Heads 15 mm. high, disk 

 25mm. broad; ray flowers 10-15, 

 disk flowers numerous. Invo- 

 lucral bracts in 2-3 series, glab- 

 rous, the outer shorter, ovate- 

 orbicular, obtuse; inner oblong, 

 obtuse or subacute. Corollas 

 yellow, ray with very short tube, 

 ligule elliptic, 3-5-4-5 cm - lon g, 

 minutely bidentate, spreading; 

 disk corollas dilated and pubes- 

 cent below, 5 lobed. Receptacle 

 convex; scales narrowly oblanceolate, 3-5 dentate, acuminate, nearly 

 as long as the disk flowers, clasping the achene. Achenes slatey 

 fuscous, 1.8x5-5.2 mm., cuneate, slightly oblique; in section un- 

 equally rhombic, the angles rounded and facets concave; appressed- 

 hirsute or nearly glabrous when mature; pappus persistent, of 2 flat 

 denticulate awns 2-4 mm. long, and 6 intermediate, fimbriate, chaffy 

 scales, 1.5-2 mm. long, or awns wanting and scales reduced forming 

 a crown. 



Hab. "Herb 15 feet high, quite shrubby, cultivated at Izamal, 

 where it blooms in November," Gaumer 944, San Anselmo 2078; culti- 

 vated in Ditas March 17, 1903, Ccec. et Ed. Seler jp?o. 



Tithonia tagetiflora Desf. Ann. Mus. Par., 1:46, t. 4. 



An erect, branching annual, with alternate, wing-petioled, ovate 

 or broad, 3-lobed, acuminate, serrate, hispidulous-puberulent leaves. 

 Inflorescence of solitary, terminal and axillary heads, peduncles clav- 

 ate, fistular at the summit, striate, densely villous. Heads 1.2-1.5 

 mm. high, disk 1.8-2.2 mm. broad, ray flowers usually 8, disk flowers 

 numerous. Involucral bracts in 2 series, the outer longer, ovate-lan- 

 ceolate, long acuminate, sericeous-villous; the inner ovate, acuminate, 

 less villous. Corollas yellow, ray with very short tube, ligule oblong- 

 oval, 2-2.5 cm - l n & minutely tridentate- or entire, spreading; disk 

 corollas dilated and villous at the base, 5 lobed. Receptacle convex; 



