THISTLE FAMILY 949 



1. S. Fremontii A. Gray. Stem 1 dm. high or less, branched from the base, 

 shghtly fioccose; leaves si)atiilate or hnear-cuneate, often 3-lobed at the summit, 

 8-15 mm. long, floccose; involucres about 6 mm. high; bracts 5, broadly oblong; 

 ligules 5, golden vellow, 4 mm. long and fully half as wide. Desertplains: Ariz. 

 —Utah— Nev.— Calif. L. Son. Ap-My. 



105. TETRANEURIS Greene. 



Perennial (all ours) or annual, caulescent or scapose, more or less villous or 

 silky herbs. Leaves usually entire, rarely some of them lobed, alternate, either 

 clustered at the base, or scattered along the stem, or both. Heads radiate, 

 rarely discoid, on slender peduncles. Involucre hemispheric, or nearly so; bracts 

 several in two subequal series; receptacle convex, naked. Ray-flowers 10-20, 

 pistillate and fertile; ligules yellow, oblong, broad, 3- (rarely 4-) toothed; nerves 

 4. Disk-flowers many, hermaphrodite and fertile; corollas with 5 short pubescent 

 teeth. Anther-tips broad, triangular or ovate. Style-branches dilated, trun- 

 cate, somewhat penicillate at the tips. Achenes obpyramidal, 5-angled, about 

 3 times as long as broad, densely hirsute. Pappus of about 5 hyaline squameUae, 

 with a strong midrib, which sometimes is produced into an awn. 



Heads ses.sile among the leaves. 1. T. dcpressa. 



Heads distinctly pedvincled. 



Stems scapiform, leafy only at the base. 

 Leaves appressed-silky. 



Leaves not strongly 3-nerved on the broadened bases. 



Leaves spatulate or oblanceolate, 2-4 cm. long; scape stout, 5-10 cm. high. 



2. T. septentrionalis. 

 Leavas linear or linear-oblanceolate; scape 10-20 cm. high. 



Leaves silvery-silky; ligules 6-8 mm. long. .3. T. acaulis. 



Leaves greenish, sparingly silky; ligules 8-10 mm. long. 



4. T. simplex. 

 Leaves strongly 3-nerved on the broadened bases, narrowly Unear-oblanceo- 

 late. 5. T. trinervata. 



Leaves loosely villous or glabrate. 



Leaves, scape, and involucre decidedly \illous. 



Involucre more than 1 cm. broad; scape 3-8 cm. long; plant densely cespi- 

 tose-pulvinate ; leaves not conspicuously broad-based. 



6. T. lanigera. 

 Involucre less than 1 cm. broad; scape 1-3 cm. (rarely 3-.5 cm.) long; 



plant loosely cespitose; leaves conspicuously broad-based. 



7. T. brevifoUa. 

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



villous only in T. Torreyana). 

 Branches of the caude.x decidedly villous at the ends, with long, at first 

 white, but later brownish hairs. 

 Pappu-s-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 caude.x not conspicuously villous. 



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

 blades; branches of the caude.x short and stout. 

 Leaves glabrous, scarcely pimctate; bracts slightly shorter than the 



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



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

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



Bases of the leaves 2-4 times as wide as the linear leaf-blades ; branches 

 of the caude.x or rootstock elongate. 13. T. fastigiata. 



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



Basal leaves oblancuohite to Linear-oblanceolate, more than H mm. wide; invo- 

 lucre hemispheric, 14. T. leptoclada. 

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

 rower. 1.5. T. Ivesiana. 



1. T, depressa (T. & G.) Greene. Pulvinate-cespitose perennial; leaves 

 narrowly linear or nearly so, 1-2 cm. long, 1-2 mm. wide, glabrate, hairy-tufted 

 at the base; heads sessile; involucres about 6 mm. high and 8 mm. broad; bracts 

 oblong, obtu.se; achenes silky-strigose ; pappus-squamellae ovate, tapering into 

 an awn. Actinella dcpressa T. & G. Dry hills and mountains: Utah. 



2. T, septentrionalis Rydb. Leaves mostly rounded at the apex, 5-8 mm. 

 wide, canescent-tomentose, subvelutinous; scape 5-10 dm. high, rather thick, 



