258 CARDUACEAE 



Leaves glabrous or sparingly villous; scape finely pubescent or villous (long- 

 villous only in T. Torreyana). 

 Branches of the caudex decidedly villous at the ends, with long, at first 

 white, but later brownish hairs. 

 Pappus-scales lanceolate, acuminate, not awned; scape villous. 



8. T. Torreyana. 

 Pappus-scales oval, awned; scape silky. 



Bracts oval. 9. T. arizonica. 



Bracts linear-oblong. 10. T. Crandallii. 



Branches of the caudex not conspicuously villous. 



Bases of the leaves not wider than the oblanceolate or almost linear 

 blades; branches of the caudex short and stout. 

 Leaves glabrous, scarcely punctate; bracts slightly shorter than the 



disk; ligules not strongly nerved. 11. T. epunctata. 



Leaves long-hairy, distinctly punctate; bracts three-fourths as long 

 as the disk; Ugules strongly nerved. 12. T. angustifolia. 



Bases of the leaves 2-A times as wide as the linear leaf-blades ; branches 

 of the caudex or rootstock elongate. 13. T. fastigiata. 



Stems 2-3 dm. high, with 2-6 stem-leaves. 



Basal leaves oblanceolate to Unear-oblanceolate, more than 5 mm. wide; invo- 

 lucre hemispheric. 14. T. leploclada. 

 Basal leaves narrowly linear-oblanceolate, less than 5 mm. wide; involucre nar- 

 rower. 15. T. Ivesiana. 



106. RYDBERGIA Greene. 



Basal leaves all dissected: plant villous. 1. R. grandiflora. 



Basal leaves, at least some of them, simple; plant more glabrate. 2. R. Brandegei. 



107. HYMENOXYS Cass. Colorado Rubber Plant. 



Perennials or biennials; inner bracts fimbriate or erose, abruptly acute, acuminate, or 

 mucronate, unlike the outer ones: disk-corollas not expanded at the mouth. 

 Plant low, perennial, usually with a miilticipital caudex; outer bracts united at least 

 one-tliird their length: plant long-hairy on the basal leaf-bases. 

 Outer bracts not strongly thickened on the back. 



Outer bracts united to the middle: free portions ovate or ovate-lanceolate. 



1. H. Richardsonii. 

 Outer bracts united about a third their length; free portions narrowl.v lance- 

 olate. 



Involucre 10-15 mm. broad; ligules 10-18 mm. long; plant 1-3 dm. high. 



2. H. macrantha 

 Invohicre 8-10 mm. broad; ligules 5-8 mm. long; plant less than 1 dm. 



liigh. 3. H. pumiltt. 



Outer bracts strongly thickened on the back, subcarinate. 



Heads few, often solitary; Ugules nearly rectangular-oblong. 



4. H. Macounii. 

 Heads several: Ugules decidedly cuneate. 



Ligules light .\cllow, at least twice as long as wide; pappus-squamellae 



aristate-pointed. 5. H. floribunda. 



Ligules orange, half longer than ivide; pappus-squameUae acute or acum- 

 inate, (i. H. Earlei. 

 Plant tall, biennial or short-lived perennials; outer bracts united only at the base. 

 Leaves all dissected into narrowly linear divisions. 



Leaves «f the stem very numerous, more or less lepidote-pubescent: segments 

 narrow, rarely more than 1 mm. wide. 

 Plant low, densely canescent: heads 1-3; squameUae not more than half 



as long as the corolla, not subulate-tipped. 7. H. canescens. 



Plant tall, greener; heads several or many; squameUae about half as long 

 as the corolla, subulate-tipped. 8. H. biennis. 



Leaves of the stem not conspicuously numerous, glabrate and green; segments 

 1-3 mm. wide. 9. H. Greenei. 



Leaves, at least the lower ones, entire or with broad lobes 3-8 mm. wide. 



10. H. helenioides. 

 Annuals, with numerous heads ; inner bracts not very different from the outer, neither 

 abruptly acute nor mucronate, nor evidently erose ; throat of the disk-corolla,s some- 

 what funnelform. 11. H. odorata. 



108. FLAVERIA Juss. l. F. campestris. 

 ^ 109. DUGALDIA Cass. l. D. Hoopesii. 



110. HELENIUM L. Sneezewebd. 



Plant scabrous-puberulent throughout; bracts about equalling the disk; ligules about 1 

 cm. long or less. 1. H. montanum. 



Plant glabrous or minutely puberulent: bracts much longer than the disk; ligules gen- 

 erally over 1 cm. long. 2. if. macranthum. 



111. GAILLARDIA Foug. Blanket-flower. 



Lobes of the disk-corollas acuminate, covered with moniliform hairs. 



Plant perennial ; ligules usuaUy wholly yellow. 1. G. arislata. 



