52 Contributions from the Gray Herbarium 
5.5-25 em. long, rarely somewhat thickened upwardly in age 
(Tithonia-like); disk 1.5—(fruit)2.5 em. high, 1.7-2.7 em. thick. 
Involucre equalling or slightly surpassing disk, 4—5-seriate, the 
3 outer rows herbaceous, more or less indurated and ribbed at 
base, oblong or ovate, with acutish to obtusish more or less involute 
spreading apex, hispid-strigillose on back, hispid-ciliate on margin, 
the two inner rows membranaceous-chartaceous, minutely tuber- 
culate-strigillose and -ciliolate, round-tipped, enlarged and siccate 
in fruit. Receptacle convex. Rays about 18, oblong to oval, 
1.5-3 cm. long, 2.5-10 mm. wide; disk-corollas yellow, sparsely 
puberulous below and on veins and teeth, 7-8.5 mm. long (tube 
2-2.3 mm.). Pales stiff, ovate-acuminate, more or less purplish- 
tinged, 9.5-11 mm. long. Achenes appressed-pubescent or gla- 
brous, 5 mm. long. Pappus present or absent; when present of 2 
awns, unequal, ciliate, 3-4.3 mm. long, and 2-3 pairs of squamellae, 
these quadrate, fimbriate, 0.9 mm. long; the awns somewhat de- 
ciduous.— Helianthus giganteus Cav. Icon. iii. 10. t. 219 (17947? = 
1795), not L. (err. iden.). H. excelsus Willd. Sp. ll. pt. 3. 2243 
(1804). Tithonia excelsa (Willd.) DC. Prod.! v. 585 (1836). 
Viguiera excelsa (Willd). B. & H. ex Hemsl. Biol. Centr.-Am. 
Bot. ii. 177 (1881); Rob. & Greenm. Proc. Bost. Soc. Nat. Hist. 
xxix. 88, 102 (1899). Helianthus trinervis Hort. ex DC. Prod. v. 
585 (1836), as syn. Gymnolomia megacephala Rob. & Greenm.! 
Proc. Bost. Soc. Nat. Hist. xxix. 102 (1899), excl. var. — Divisible 
into three varieties. 
a Var. genuina: caule tuberculato-strigoso vel -strigilloso vel 
dense bifariamque hispido-piloso; foliis anguste oblongis vel lan- 
ceolatis 5.5-11.7 cm. longis 1.5-3.1 em. latis, ut videtur semper 
alternis (inferioribus non visis). — Helianthus giganteus Cav. l. c. 
H. excelsus Willd. 1. c. H. trinervis Hort. ex DC. 1. c. Tithonia 
excelsa (Willd.) DC. 1. c. Viguiera excelsa (Willd.) B. & H. 1. ¢.— 
MEXICO: Strate or Mexico: San Angelo, Berlandier 940 
(authentic for T. excelsa DC.: B. M., G., Prod.); 1. ¢., Aug. 1855, 
Schaffner 74 (G.); 1. ¢., 1 Aug. 1865, Bourgeau 599 (K.); hills near 
Santa Fe, 8 Sept. 1865, Bourgeau 843 (G., K.); Cuantitlan, 12 Nov. 
1827, Berlandier 1265 (K.); Valley of Mexico, 187—, Schaffner 
296 (K.); Pumpua: grassy hills, Esperanza, Sept. 1907, Purpus 
2794 (B. M., G., Mo., U. S.). Cunrrvarep: ue Can 
(Mo., ex hb. Bernhardi.). 
