AND GENERA OF PLANTS. 297 
Tripolium conspicuum, also comes in this section; remarkable for the great 
inequality of the sepals, which are coloured at the tips. Achenium scarcely 
compressed, pubescent, very slenderly five-striate. 
Tripolhum *imbricatum; like the preceding, but with the long, linear, am- 
plexicaule leaves distantly serrulate; branches somewhat corymbose; involu- 
crum turbinate, closely imbricated in four series of acute, oblong sepals, pale 
below, and coloured or herbaceous at the tips; rays narrow and short. Ache- 
nium subcylindric, five-striate. 
Has. In Chili, near Valparaiso, (Dr. Styles.) Allied to the preceding, but with a very differ- 
ent involucrum and much larger capitulum. 
* XYLORHIZA. . 
Capitulum radiate, rays feminine, fertile, the liguli in one series, rather large, 
toothed at the point; florets of the disk five-toothed, hermaphrodite, fertile. 
Apex of the stigma conic-lanceolate, narrowed. Involucrum widely hemi- 
spherical, sepals nearly equal, herbaceous, imbricated loosely in two series, 
acuminated, the inner ones with membranaceous margins. Receptacle flat, 
alveolate. Achenia subterete, silky, not marginated. Pappus of several se- 
ries, unequal, scabrous.—Herbaceous subalpine plants, with woody roots, 
sending out numerous dwarf, simple stems, terminating in one, or a small 
corymb of large flowers. Leaves linear, entire; disk yellow. Ligule rose- 
coloured, or pale purple.—( So called from £vA0r, wood, and pifov, a root. The 
root only being woody.) 
Oss.—Allied to Calimeris, which it represents, differing somewhat in habit, 
and wholly in the fruit. From Aplopappus it differs in its heterochromous 
flowers, and more slender, not paleaceous pappus, as well as in habit. 
Aylorhiza * glabriuscula; base of the stem and primary leaves only pubes- 
cent; leaves oblong-linear, or lanceolate-linear, acute, coriaceous; peduncles 
solitary or corymbose, three to five; sepals lanceolate, much acuminated. 
Has. In arid, argillaceous tracts in the Rocky Mountains, and on rocks toward the sources of 
the Platte. Flowers large, the rays pale rose-colour. Root thick and stout, woody, sending up 
clusters of low, simple stems, terminating in one to five flowers; leaves about two inches long, two 
VIL.—3 Z 
