BLAKE—REVISION OF TITHONIA. 425: 
Phyllaries 3 to 5-seriate, graduated, at least the inner with rounded or rarely acute, 
broadened, more or less membranaceous-chartaceous or rarely subherbaceous 
tips. 
Petiole bases strongly auriculate-decurrent.................-- 8. T. brachypappa. 
Petiole bases sometimes auriculate but never decurrent. 
Pappus present. 
Leaves unlobed. 
Plant annual; stem sparsely hispid-pilose.................. 4. T. thurberi. 
Plant shrubby; stem densely and canescently pilose-tomentose. 
9. T. fruticosa. 
Leaves 3 to 5-lobed, or the upper sometimes entire. 
Leaves densely and usually canescently pilosulous beneath. 
10. T. diversifolia. 
Leaves green beneath, merely sparsely puberulous or nearly glabrous 
except on the veins...............+.- 10a. T. diversifolia glabriuscula. 
Pappus none. 
Innermost phyllaries acute or rarely obtuse at apex. 
Leaves lance-ovate to ovate, distinctly petioled. 
Stem densely silky-villous with long spreading hairs; disk 2.5 to 3 cm- 
thick. ..... 2. 2. c cece ec ec ee eee eee eee e eee eeees 5. T. calva. 
Stem hispid-pilose or pilose with short hairs; disk 1.2 to 2.2 cm. thick. 
5a. T. calva lancifolia. 
Leaves linear-lanceolate to lance-ovate, subsessile, cordate-auriculate at 
DABC.. 0. eee cee ee eee ee eee eee e eee e ences 6. T. auriculata. 
Innermost phyllaries broadly rounded at apex. 
Heads medium-sized, the disk 1.1 to 2 cm. thick; stem hispidulous and 
sparsely hispid-pilose...............-----2222eceeeeeeeee 7. 'T. pittieri. 
Heads large, the disk usually 2 to 3.5 cm. thick; stem usually densely 
hispid-pilose.............. 2.202 e eee eee cee eee ees 8. T. scaberrima. 
1. Tithonia tubaeformis (Jacq.) Cass. Dict. Sci. Nat. 35: 278, 1825. 
Helianthus tubaeformis Jacq. Pl. Hort. Schénbr. 3: 65. pl. 375. 1798. 
Tithonia helianthoides Weinm.; Steud. Nom. Bot. ed. 2. 2: 689. 1841, as synonym. 
Urbanisol tubiformis Kuntze, Rev. Gen. Pl. 1: 371. 1891. 
Tithonia tubacformis var. bourgaeana Pampanini, Bull. Soc. Bot. Ital. 1908: 134. 
1908. 
_ Erect branching annual, 1 to 2 meters high; stem densely and rather harshly hispid- 
pilose with spreading hairs with several-celled subglandular base, in age subglabrate 
below; leaves alternate, the blades 7 to 18 cm. long, 3.8 to 14.8 cm. wide (excluding 
the margined apex of the petiole), ovate to deltoid-ovate, not lobed, acuminate, 
cuneately narrowed from a truncate or subcordate base into the petiole, crenate- 
serrate or dentate, 3-nerved, deep green above, harshly hispid-pilose with slightly 
tuberculate-based hairs, beneath paler, densely gland-dotted, canescent or subcanes- 
cent with dense incurved hairs, in age often green, subglabrate, and harsh, the upper- 
most much smaller and lanceolate; petioles hispid-pilose, subglabrate, scarcely 
margined below, 1.5 to 10 cm. long; peduncles usually strongly clavate above, densely 
and canescently hispid-pilose near the head, 30 cm. long or less; heads 4 to 9 cm. 
wide; disk in anthesis 1.2 to 1.8 cm. high, 1.5 to 3.3 cm. wide, in fruit 1.5 to 2.5 cm. 
high; involucre 2 or 3-seriate, 1.5 to 3 cm. high, densely and canescently pilose or 
hispid-pilose with long spreading hairs, the phyllaries lanceolate or oblong-lanceolate 
(1.5 to 4, rarely 5.5 mm. wide), acute or acuminate, subequal or obgraduated, with 
indurate ribbed base and longer, slightly broader, loose, herbaceous tip; rays 12 to 
14, golden-yellow or orange, elliptic, 3.3 cm. long or less; disk corollas yellow, slen- 
derly tubular, hispidulous chiefly on the swollen base of the throat, subglabrous 
