THISTLE FAMILY 949 



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

 slightly floccose; leaves spatulate or Unear-cuneate, often 3-lobed at the summit, 

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

 ligules 5, golden yellow, 4 mm. long and fully half as wide. Desert plains : 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, hennaphrodite 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-angIed, about 

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

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



Heads sessile among the leaves. 1. T. depressa. 



Heads distinctly peduncled. 



Stems scapiform, leafy only at the base. 

 Leaves appressed-silky. 



Leaver 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. 



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



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



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



4. T. simplex. 



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

 late. 5. T. trinervata. 

 Leaves loosely villous or glabrate. 



Leaves, scape, and involucre decidedly \iUou3. 



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



tose-pul\'inate; 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. brevifolia. 



Leaves glabrous or sparingly vihous; scape finely pubescent or viUous (long- 



villous only in T. Torreyana). ^ ^ ^ 



Branches of the caudex decidedly viUous at the ends, ift^th long, at first 



wliite, but later brownish hairs. 

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



8. r. Toneyana^ 



Pappus-scales oval, awned; scape silky. 



Bracts oval. 0. T. arizomca,^ 



Bracts linear-oblong. 10. T. Crandalht. 



Branches of the caudex not conspicuously villous. 



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



blades; branches of the caudex short and stout. 

 Leaves glabrous, scarcely punctate; bracts slightly shorter than the 



disk; ligules not strongly nerved. 11. T, € punctata. 



Leaves long-hairy, distinctly punctate; bracts three-foiun^hs as long 

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



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

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



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



Basal leaves oblanceolate to linear-oblanceolate. more than 5 mm. wide; mvo- 



lucre hemispheric. , 14- T. leptoclada. 



RT-*ial le-aves narrowly linear-oblanceolate. less than 5 nun. wide; mvolucre nar- 

 rower. 1^' ^- ^^e^^^jna. 



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

 narrowly Unear 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 

 oblone; obtuse: achenes silky-strigose ; pappus-squamellae ovate, tapering mto 

 an a\ra. Aciinella depressa T. & G. Dry hills and mountams: Ltah. 



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

 _-j„' '«^o«r.r.+_fr.m^T^+nQP siihvf^hitinoua: scaoe 5-10 dm. high, rather thick, 



