182 NORTH AMERICAN FLORA [VoLUME 34 
and sessile, with pellucid glands along the margins and sometimes also scattered ones on the 
surface. Heads discoid. Involucre cylindric or campanulate; bracts few, 5-9, linear, oblong, 
or obovate, distinct or connate only at the base, usually with 2 dorsal rows of glands. Re- 
ceptacle small, naked. Flowers all hermaphrodite and fertile. Corollas yellowish or purplish, 
actinomorphic or slightly bilabiate, the limb being cleft more deeply on the two sides of a single 
lobe, the throat varying from funnelform and much shorter than the tube to cylindric and 
longer than the tube. Arthers rounded at the base. Style-branches long, filiform-subulate, 
hirtellous. Achenes narrow, often tapering at the apex, many-striate, commonly hispidulous. 
Pappus of numerous scabrous or hispidulous bristles. 
Type species, Cacalia Porophyllum L. 
Throat of the corolla more or less funnelform, usually much shorter than 
the slender tube; corollas from ochroleucous or white to purple. 
Leaf-blades oval to elliptic or lanceolate, slender-petioled; corolla-tube 
several times as long as the broadly funnelform throat (EUPORO- 
PHYLLUM). 
Annuals, 
Peduncles clavate-thickened under the involucres; heads erect; 
involucre 15—25 mm. long. 
Leaf-blades broadly oval or obovate, sinuate, crenate; 
achenes fully 1 cm. long; pappus sordid-brown; bracts 
acute or obtuse. 
Achenes pubescent. if 
Achenes glabrous. 2. 
Leaf-blades elliptic or oblong, more gradually tapering at 
the base; achenes 7—-8.5 mm. long; pappus straw-colored; 
bracts acuminate. 3. P. Porophyllum. 
Peduncles filiform throughout; involucre 10-18 mm. long. 
Heads and peduncles erect. 
Involucre 15-18 mm. long, 2 mm. broad; flowers about 
. macrocephalum. 
. leiocar pum. 
hy 
12, white. 4. P. Pringlei. 
Involucre 12-14 mm. long, 3-4 mm. broad; flowers 18-20, 
deep-purple. 5. P. calcicola. 
Heads and peduncles spreading. 6. P. quinqueflorum. 
Perennials, mostly shrubby. 
Flowers subracemose, in clusters with ascending branches; heads 
distinctly nodding; leaves without glands except along the 
margins; flowers greenish. 
Leaves comparatively thick, distinctly reticulate. 7. P. viridiflorum. 
Leaves thin, not conspicuously reticulate. 8. P. nutans. 
Flowers either in cymose clusters with spreading branches, or 
solitary; heads not nodding. 
Corollas pale with darker lines or streaks. 
Leaf-blades oval or elliptic, mostly rounded at the apex; 
bracts obtuse or acute (except in P. Ervendbergii). 
Leaves with glands on the surface as well as along the 
margins. 
Leaf-blades oval or broadly elliptic, rather firm. 9. P.nummularium, 
Leaf-blades oblong or narrowly elliptic, thin. 
Bracts acute; involucre 5 mm. broad. 10. P. oblongum. 
Bracts acuminate; involucre 3 mm. broad. ll. P. Ervendbergii. 
Leaves with marginal glands only. 
Heads mostly cymose. 
Branches and peduncles divaricate; pappus 
straw-colored. 12. P. divaricatum. 
Branches and peduncles ascending; pappus 
sordid. 13. P. Millspaughii. 
Heads solitary. 14. P. jorullense. 
Leaf-blades lanceolate, acutish; bracts acuminate. 15. P. Palmeri. 
Corollas purple. 
Leaf-blades more than 1 cm. long; bracts acute; peduncles 
elongate. 16. P. Nelsonii. 
Leaf-blades less than 1 cm. long; bracts acuminate; 
peduncles short. 17. P. Pittieri. 
Leaf-blades oblanceolate, linear, or filiform, rarely lanceolate, short- 
petioled or sessile; corolla-tube not several times as long ds the 
elongate-funnelform tube (HUNTERTA). 
Leaves not filiform, more or less short-petioled. 
Heads short-peduncled in dense cymes; bracts light-green, not 
carinate and scarcely gibbous at the base. 
Corollas whitish. 
Leaves (at least the lower) lanceolate, distinctly petioled. 18. P. brachypodum. 
Leaves narrowly linear-oblanceolate, subsessile. 19. P. pausodynum. 
Corollas ochroleucous. 
