790 Walks Round San Francisco. [ December, 
rattle in the wind and the name of “rattle-weed” has thus 
arisen. A third name is the Spanish title of “loco” or “mad” 
plant, from the effects of its poisonous foliage upon the hungry 
cattle which are occasionally tempted by its green foliage and 
succulent stems—green and succulent when all around is brown 
and scorched, when even the “burrs” of the burr-clover (Medi- 
cago denticulata) are scarce and baked to chips, and the bents of 
grass are broken down into chaff—to feast upon what in times of 
greater plenty they avoid. 
Although, broadly speaking, there are no trees on the peninsula 
of San Francisco, except the thickets of scrub oak (Quercus 
agrifolia) which clothe some of the more sheltered hills and val- 
leys, yet the ravines of the few permanent springs display a crop 
of willows, mingled with a few examples of Myrica californica ; 
and cliffs with a northern aspect are in some spots made beautiful 
by an abundant growth of Heteromeles arbutifolia, a showy 
rosaceous shrub, with red berries like the European hawthorn, 
but no thorns. Earlier in the season it blooms into a mass 
of showy bunches. 
Ceanothus thyrsiflorus, a few starvling plants of which may be 
found among or near the willows, is, in more favored localities, 
one of the loveliest of shrubs, or rather trees, for it grows to the 
size of an apple tree. Covered all over with lilac-like bunches of 
odoriferous blue flowers (whence its local name of “blue myr- 
tle”), and growing in extensive thickets over terraces and 
uplands, it is a living contradiction of the theories of color 
purists who deny that blue flowers and green leaves can be 
beautiful. 
If we pick our way through the sand and over the hard-baked 
bed of what in winter is a watercourse, to one of the little coves 
which lie between the cliffs, we shail probably find numerous 
specimens of the curious little crustacean, Hippa analoga Stimp- 
son. This little fellow lives in the sand between tide-marks, and 
although in the vernacular confounded with the species of 
Orchestia and Allorchestes, under the general term of “sand 
hopper,” really belongs to a very different and higher division of 
- the class Crustacea than that which includes his companions of 
the sand. He, or rather she, for the female is much the larger, 
has the body longer than wide, a narrow abdomen tucked under 
_ the body like that of an ordinary crab, five pairs of limbs, eyes 
