VOL. l] Naturalized Plants. 57 



planted it for ornamental purposes, but learning its dangerous char- 

 acter, carefully destroyed the plant before the end of the summer. 

 They had however scattered considerable seed and the next spring 

 there was an abundant crop. Constant vigilance was exercised to 

 destroy them belore they could produce seed and has been exercised 

 annually since, but every year a few vines continue to make their 

 appearance where the first ones were planted twelve years ago. Al- 

 though so persistent when once introduced it confines itself to par- 

 ticular localities, and does not tend to become commonly diffused, 

 as do weeds whose seeds are better provided with facilities for trans- 

 portation. In most cases where it has become a weed its origin is 

 probably directly due to cultivation as a flower. 



Of the Mustards, two species are common all through this region. 

 Hardly a grain field is entirely free from Brassica iiigra, and on the 

 rich adobe lands of Los Angeles it is exceedingly luxuriant and 

 abundant, in places taking entire possession of the soil and overtop- 

 ping horse and rider. B. campcstris is mainly a wayside weed, 

 somewhat less common than the former species, but in my neighbor- 

 hood increasing of late years. B. adpressa has been observed only 

 about San Bernardino, where it is quite common by roadsides. A 

 fourth series, B. sinapistnim is reported^ as *' sparingly naturalized 

 in Southern California," but it has not been found, so far as I can 

 learn, in the counties to which I have restricted that term, and is ex- 

 eluded from tlie list of our weeds. 



The Fuller's Teasel ( Dipsacus Fullomtm) seems to have estab- 

 lished itself only about San Diego. It has been collected at Los 

 Angeles by Mr. Lyon, but as an evident escape. At San Diego Mr. 

 Cleveland obtained it as long ago as 1876 among the stony hills of ■ 

 the Cajon Valley, where it is still growing, and Mr. Orcutt reports 

 it as naturalized at the Old Mission. 



San Diego being a seaport is more exposed to the invasion of for- 

 eign plants than are the inland towns, and, as might be expected, it 

 does in fact afford a number of species not known elsewhere in the 

 southern counties. The most interesting of these is SoncJms iejier- 

 rimtis, for which San Diego is the only known station in the synop- 

 tical region. Collected long ago by Nuttall, who published it as an 

 indigenous speciesf it escaped the notice of succeeding botanists, 

 until recently rediscovered by Mr, Orcutt. Yet according to him it 



*Bot. Cal., ii, 40. tTrans. Am. Phil. Soc. vii, 438. 



