386 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Leaves filiform —--~_~------- ~~~ 2a. 
Leaves linear. 
Stems glabrous except on and near the pedicels — 2. 
Stems scabrate almost throughout ~~ ~~ ______ vb. 
Perianth not scarlet: campanulate. 
Leaves linear or narrowly linear-lanceolate. 
Inflorescence paniculate or Cymose. 
Fruit glabrous. 
Plant low and slender; leaves linear: inflores- 
A. gracillima filifo- 
lia. 
A. gracillinu. 
A. gracillimea sca bri- 
data, 
cence cymose, i.e, its branches alternate. 3. A. petrophila. 
Plant tall and stout; leaves wider and thicker ; 
inflorescence paniculate, i. e.. with opposite 
branches_ ~~~. oe. 
Fruit not glabrous. 
Plants tall, erect, stout; stems simple or spar- 
ingly branched: inflorescence paniculate; 
leaves sessile. 
Stems glabrous below___________________ D. 
Stems more or less hirsute below —~_______ | Da, 
Plants lower; stems more branched and diffuse, 
or the inflorescence cymose. 
Leaves divaricate, distinctly petioled ; 
branches of the inflorescence merely viscid- 
puberulent_——~--_--_--_-- ee 6. 
Leaves mostly erect, sessile; branches of the 
inflorescence densely viscid hairy. 
Plant low; leaves thick and dull green___ 7. 
Plant larger and much more branched; 
leaves thin and bright green_________ S. 
Inflorescence axillary or of few-flowered clusters 
at the ends of the branches. 
Lobes of the involucre elliptical, rather obtuse; 
plants very slender, the stems simple or spar- 
ingly branched ~~ ~~-_~ ~~~ ee 11. 
acute; plants much branched. 
Involucre covered with long and soft hairs; 
leaves more or less subpilose; fruit with 
thick, smooth ribs, obtuse. -.~~---_-_ 9, 
Involucre puberulent; leaves glabrous; fruit 
with narrower and less conspicuous ribs, 
neute 10. 
Leaves neither linear nor narrowly linear-lanceolate, 
Inflorescence axillary. 
Stems hirsute______-___--____- eee 12. 
Stems not hirsute. 
Stems glabrous below. 
Stems slender, sparingly branched; leaves 
glabrous____--___--_-- ee 13. 
oo A glabra. 
A. linearis, 
A. linearis subhis- 
pida, 
A. diraricata, 
“A. diffusa, 
A. glandulifera, 
AL pinetorum. 
A. vaseyi. 
A. bodini, 
A. aggregata, 
A. decumbens, 
