IMMIGRANT PLANTS IN LOS ANGELES COUNTY, CALIFORNIA. 57 
where undisturbed may be said to flourish most luxuriantly 
on moist clay banks; in such places forming thickets six to 
ten feet high, impenetrable as brushwood, and affording 
nesting sites for blackbirds and sparrows, which, feeding 
upon the seeds, help to further disseminate the plague. In 
many grain fields the loss it occasions is considerable, and 
can only be prevented through the tedious process of weed- 
ing by hand. B. campestris, L., common enough in the 
city of Los Angeles, and adjoining lands, can not as yet be 
considered troublesome. 8. alba, L. Already reported by 
Dr. Hasse as found at Santa Monica. 
Sisymbrium officinale, Scop. This plant reported by Dr. 
Hasse from Mandeville Cajion, I had found two years ago at 
Millards Cafion. In both places it is increasing rapidly. 
S. acutangulum, DC., though discovered here by Brewer 
about 1860, remained obscure until three years ago, when I 
found it not infrequent in various parts of the city of Los 
Angeles. It flowers early in the season when the growth of 
grass, etc., is rank, and its inconspicuous flowers are easily 
overlooked, which probably accounts for its not having been 
more frequently observed. 
Bursa pastoris, Wigg. Very common, and here, as in its 
native haunts, it is easily crowded out by other plants; and 
80, with us, is commonly found, along with the Crotons and 
Lepidiums, in the dry and sandy wastes. 
Nasturtium officinale, R. Br., flourishes in the quieter 
waters of all our streams, covering them with a mantle of 
green all summer. 
Raphanus sativus, L. Widely dispersed and thoroughly 
established, and by its flowering and fruiting all the year 
round, it bids fair to become one of the most troublesome of 
weeds. 
Silene Gallica, L. Frequent in sandy soils. 
Stellaria media, Cyr. This is fairly common but the con- 
ditions necessary to its maintenance, naturally limits its 
range in our rather dry climate; so that it has not spread 
beyond shaded places in arroyos adjoining the city. 
