368 COMPOSITZ PETASITES 
78 Petasites Flowers white or purplish, the fertile ones pistillate and 
more or less conspicuousely radiate. 
* * Heads discoid, of wholly hermaphrodite fertile yellow fowers. 
79 Cacaliopsis Heads very many-flowered: anthers entire at base. 
80 Luina Heads about 10-flowered: anthers sagittate at base. 
81 Rainieria Heads 4-6-flowered: achenes prismatic. 
* * * Heads heterogamous or homogamous: the tubular disk. flowers 
perfect and fertile, with 2-cleft style. 
82 Crocidium Herbs with alternate leaves: heads radiate many-flower- 
ed: flowers yellow, all fertile, involucre hemispherical or more open. 
83 Tetradymia Shrubs with alternate leaves: involucre of 4-6 firm and 
concave close and overlapping bracts. 
84 Raillardella Herbs with alternate leaves: involucre of a single ser- 
ies of linear equal bracts, their edges lightly connate below the middle: 
pappus of comparatively few and usually stout plumose bristles. 
85 Arnica Herbs with chiefly opposite leaves: involucre of seyeral thin 
herbaceous equal bracts: pappus a single series of numerous capillary 
scabrous to barbellate brisiles. 
86 Senecio Herbs with alternate leaves: involucre of several erect her- 
baceous bracts: pappus of soft-capillary merely scabrous bristles. 
* Style-branches of hermaphrodite fertile flowers roundish-obtuse , 
or at least not truncate, wholly without appendages or hispidity at 
summit. Receptacle naked, flat. Pappus-bristles merely denticulate 
78 PETASITES Geertn. Fr. ii, 406, t. 166. 
Perennial herbs with thickish and most'y creeping rootstocks 
sending up scapiform foliose: bracteate simple flowering stems and 
ample radical leaves on long petioles in early spring. Heads ra- 
cemosely or corymbosely disposed, white or purplish-flowered, 
subdiccious ; those of the truly fertile plant wholly or mostly of 
_pistillate flowers with slender tubular and irregularly 2—5-toothed 
or distinctly ligulate corolla; in the substerilé with few of these 
in the margin and numerous hermaphrodite infertile ones with 
2-cleft or 2-lobed style and sterile ovary in the centre. Involucre 
a series of soft herbaceous bracts. Achenes narrow, 5-10-costate. 
Pappus of soft and white elongated bristles. 3 
P. sagittata Gray Bot, Cal. i, 407. Scapes very scaly, 3-10 inches 
high; leaves deltoid-ovate or reniform-ovate, persistently white-tomentose 
beneath, glabrous or nearly so above, 4-10 inches long, their margins sin- 
uate denticulate, neither cleft nor lobed: heads short-racemose, becoming 
corymbose: involucre campanulate: flowers nearly white, the marginal 
ones of the pistillate heads ligulate but not surpassing the disk. Wet 
grounds, northern Washington to Alaska and across the Continent. 
P. patmata Gray |. c. Stems very scaly, stout, 6-24 inches high: 
leaves nearly orbicular in outline, 6-18 inches in diameter, 7-11-cleft to 
beyond the middle or deeper; the lobes oblong-lanceolate to oblong-cune- 
ate, laciniately dentate, white-tomentose beneath, green and glabrate. 
above: heads rather numerous, in a fastigiate panicle, about 6 lines high. 
ly le Det ell 
