THISTLE FAMILY 935 



beneath, 3-7 cm. long; heads few, paniculate; involucres scarcely 1 cm. high, 

 1.5 cm. broad; ligules orange, 12-15 mm. long. Verbesina encelioides exauriculata 

 Robins. & Greenm. Mountain valleys: Mont. — Tex. — Ariz. Son, — Mont, Je-0. 



78. COREOPSIS L. Tickseed. 



Annual or perennial herbs. Leaves various. Heads on long peduncles, 

 radiate. Involucres campanulate, their bracts in two series, all more or les# 

 united at the base, the outer ones usually narrow and foUaceous, the inner broad^ 

 variously colored, in ours orange or brown, scarious or with scarious margins, 

 Ray-flowers neutral; ligules yellow. Disk-flowers fertile. Receptacle flat or ^ 

 slightly convex. Achenes flat or more or less convex on the back. Pappus of 

 two fimbriate squamellae, two awns or minute teeth, or none. 



Leaves pinnatifid. 

 Achenes winged. 

 Achenes wmgless 



Leaves simple. 



1. C. Aikinsoniana 



2. C. tinctoria. 



3. C. lanceolate. 



1. C. Atkinsoniana Dougl. Annual or perennial (?), with a taproot; stem 

 4^10 dm. high, glabrous; leaves opposite, pinnately or bipinnately di\ided into 

 linear divisions, glabrous; involucres about 6 mm. high, 15 mm. broad; outer 

 bracts oblong, obtuse, the inner broadly ovate; ligules orange, 12-15 mm. long. 

 River banks: B.C. — N.D.-— Ore. Plain. Jl-Au. 



tinctoria 



4-10 dm. high 

 ed into linear 



glabrous; involucres about 7 mm. high, 10-15 mm. wide; outer bracts oblong, 

 in fruit reflexed; inner bracts ovate or lance-ovate, acute; ligules 8-12 mm. long, 

 orange, with or without purple base. Low ground: Man. — Va, — Tex. — Ariz, 

 e B.C. Plain. Je-Au. 



3. C, lanceolata L. Perennial, with a short rootstock ; stem 2-5 dm. high, 

 glabrous; leaves opposite, the lower spatulate or oblanceolate, petioled, the upper 

 linear-lanceolate or linear, obtuse; involucres 8 mm. high and 12-15 mm. broad; 

 outer bracts lanceolate, only sUghtly shorter than the ovate-lanceolate mner 

 ones; hgules orange, 12-25 mm. long, coarsely toothed; achenes broadly wing- 

 margined; pappus obsolete. Rich soil: Ont.— Fla.— La.— N.M.— Colo. Plain. 



My-Au, 



79. BIDENS L. Beggar-ticks, Bur-marigold. 



r 



Caulescent herbs, ours all annual. Leaves mostly opposite, simple or pinna- 

 tifid. Heads numerous, radiate or discoid. Involucres campanulate or tur- 

 bmate, of two series of bracts, distinct or united only at the very base, the outer 

 fohaceous, the inner scarious and appressed. Receptacle flat, chaffy. Ray- 

 flowers neutral; ligules yellow or white, or none. Disk-flowers hermaphrodite 

 and fertile. Achenes flat, 4-angled, or rarely ahnost terete, beakless. Pappus 

 of 2-4 (in ours retrorsely) barbed awns or teeth, rarely none, 



Achenes flat, obovate or cuneate; leaves or segments broad. 



Leaves pinnately 3-5-foliolate. , , , , . „ fmn^nKn 



Outer bracts 4-8; achenes nearly black. 1. B. fronaosa. 



Outer bracts 10-16; achenes brown. -2. ^' vmgaia. 



^^H^ads^cSscoid, erect; coroUa 4-toothed; achenes not tubercled. 3. B. comosa, 

 wpA/is usuallv radiate, nodding; corolla 5-toothed. ^ _ , 



Out^ bracts not much lon|er than the inner; achenes not corky o^^the^^^gle^ 



Outer bracts surpassing the rays; achenes with corky angles. ^ gj^^^^scens. 



/ 



lenes Unear. tetragonal ; leaf-segments smaU. Bioelovii 



Divisions of the leaves oblong or lanceolate. 6. B. ^;_fff »;»^ 



rviiricinns nf the leaves linear. 



7. B. tenuisecta. 



lum 



1 B frondosa L. Annual; stem d-lU dm. lugn; leaves ^ 

 late, 'glabrous or nearly so, scabrous on the margins; leaflets 3-8 cm. long lanceo- 

 late or oblong-lanceolate, sharply serrate, acummate; myolucres 10-15 mm. 

 u:l ^^A K.^3. ^i,+.>r hrants 4-8. snatulate-lmear. entire, ciliate; hgules usually 



