Compositta—Achillea. 251 
fifty, dispersed over Europe, temperate Asia, and North America. 
The name is of classical origin. 
1, A. Millefolium. Yarrow.—The pink- or purple-flowered 
varieties of this common weed are equally effective with any of 
the other species and of long duration. The leaves are tri- 
pinnately divided into numerous linear segments and the 
flowers usually white. 
2. A. filipendulina (fig. 138).—This is very near the pre- 
ceding but rather taller and having less finely-cut leaves, and 
pretty bright yellow flowers. 
A. Aigyptiaca and A. tomentosa are dwarf tufted species with 
finely-cut cottony leaves and yellow flowers. 
3. A. Ptérmica. Sneezewort.—The only other native 
species. The leaves are simple and serrulate, the ray-florets 
larger, and the flower-heads larger and less numerous. There 
is a double white variety of this worthy of cultivation. 
4, A. Clavénne.—A dwarf species belonging to the same 
group as the last. It grows about 6 inches, and is densely 
clothed with a white hoary tomentum. Leaves bipinnatifid. 
Segments broader than in the other species enumerated. 
26. SANTOLINA. 
Small evergreen shrubs with solitary spherical rayless flower- 
heads on long peduncles. Achenes terete, destitute of pappus. 
Corolla-tube with a hood-like appendage on the base. The 
species are all natives of the Mediterranean region. The name 
is combinative of sanctus, holy, and linwm, flax, in allusion to 
the reputed medicinal properties of some species. 
1. 8. Chamee-cyparissus. Cotton Lavender.—A dwarf densely- 
branched shrub clothed with a close hoary pubescence. Leaves 
alternate, dense, linear, with 4 or 6 rows of short obtuse teeth 
projecting in all directions. Flower-heads yellow, on peduncles 
from 6 to 12 inches long. There are several varieties under 
different names, as incana, sqguarrosa, ete. 
S. alpina is a prostrate species with deeply-cut leaves and 
erect flower-stalks. 
Lasthénia glabrata is a showy hardy annual from California. 
Leaves linear, opposite. Flowers yellow. 
27. CHRYSANTHEMUM (Pyréthrum). 
Annual or perennial herbs, rarely frutescent. Leaves various. 
Involucral bracts many, imbricated, scarious on the margin. 
