424 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
the Botany of the Herald, founded on it the subgenus Mirasolia, 
characterized by its glabrous epappose achenes. In Bentham and 
Hooker’s Genera Plantarum Mirasolia was raised to generic rank, 
and included Schultz’s species and one earlier described by Bentham 
as Tithonia scaberrima. Schultz’s name Perymeniopsis, published only 
in synonymy by Klatt, was, if Klatt’s disposition may be trusted, 
based on the latter species. Tithonia was taken by O. Hoffmann in 
the Pflanzenfamilien to include both pappose and epappose species, 
and the propriety of this treatment has been shown by the writer in 
the introduction to his Revision of Viguiera cited above. 
The name Tithonia, from Tithon, consort of Aurora, was given by 
Desfontaines in allusion to the orange rays of his species. Otto 
Kuntze, rejecting Tithonia because of the use by Linnaeus in 1735 of 
the name Tithona for the genus later named by him Rivina, proposed 
Urbanisol as a substitute, a name which may be relegated to 
synonymy under both the American and the International Codes of 
Nomenclature. 
SYSTEMATIC TREATMENT. 
TITHONIA Deaf. 
Tithonia Desf. (Juss. Gen. Pl. 189. 1789, hyponym); Gmel. Syst. Nat. 1259. 1791. 
Tithonia subgenus Mirasolia Schultz Bip.; Seem. Bot. Voy. Herald 305. 1856-57. 
Mirasolia Schultz Bip.; Benth. & Hook. Gen. Pl. 2: 367. 1873. 
Urbanisol Kuntze, Rev. Gen. Pl. 1: 370. 1891. 
Herbaceous or shrubby; leaves alternate or sometimes opposite below, linear- 
lanceolate to ovate, triplinerved; heads medium or large, heterogamous, yellow, the 
rays neutral, 1-seriate, the disk flowers numerous, fertile; involucre hemispheric or 
broadly campanulate, 2 to 5-seriate, graduated or subequal, the phyllaries lanceolate 
to oblong or oval, indurate, ribbed, and vittate below, with herbaceous or mem- 
branaceous-chartaceous, rounded to acute tips; receptacle convex, the pales rigid, 
striate, usually aristate-acuminate, concave and embracing the achenes, persistent; 
ray corollas 8 to 20, oblong to oval, emarginate or tridenticulate; disk corollas with 
slender tube, longer cylindric or funnelform throat, and 5-toothed limb; anthers 
cordate-sagittate at base, with ovate appendages; style branches slender, recurved, 
dorsally hispid above, with lanceolate or linear-lanceolate, acuminate, hispid sterile 
appendages; achenes oblong, strongly thickened or subquadrangular, pubescent or 
glabrous; pappus of one or two paleaceous awns and 4 to 12 free or united squamellae, 
or of more or less united squamellae only, or entirely wanting. 
Type species, Tithonia uniflora Gmel., which is JT. rotundifolia (Mill.) Blake. 
KEY TO SPECIES. 
Phyllaries 2 or 3-seriate, subequal or the outer longer, all with long loose acute her- 
baceous tips, or the inner rarely with mucronulate or obtuse membranaceous- 
chartaceous tips, but then shorter than the outer. 
Leaves ovate, long-petioled; involucre 1.3 to 3 cm. high; pappus present. 
Involucre and apex of peduncles densely hispid-pilose with long hairs; pale 
long-aristate; leaves not lobed..........................1. T. tubaeformis. 
Involucre and apex of peduncles pilosulous or rarely short-pilose, in age often 
glabrate; pales acuminate to short-aristate; leaves often 3-lobed. 
2. T. rotundifolia. 
Leaves linear-lanceolate to narrowly lance-ovate, subsessile by a cordate-auriculate 
base; involucre 7.5 to 9 mm. high; pappus none............ 6. T. auriculata. 
