THE PIONEER PERIOD 



Tlu" liiicolic i)crio(l of (.'alifornian history was rudely brought to an end by 

 the inrush of gold- seekers from all <iuartcrs of the globe, following the discovery 

 of the precious metal in 184S. Whether they arrived by water or by the overland 

 trails, they must have brought in their belongings the seeds of new weeds, which 

 were further added to by tlie sudden Cf)mmerce which sprang up to supply their 

 needs. In these ways many cosmopolitan weeds must have made their appear- 

 ance at the port of San Francisco, and in the mining camps. The southern coun- 

 ties attracted little of this new population, for here the mines were few and unim- 

 portant, and so they were not much affected by the accompanying invasion of 

 alien i)iants. .Some of these speedily worked their way down the coast, thus 

 reversing tlic direction of the migrations of the mission jieriod. This process of 

 extension is still uncompleteil. 



For this period we have a considerable body of botanical literature. No pros- 

 pector, it is true, turned from the mad rush for wealth to regar<l the plants he 

 uprooted in his search; but there were not wanting a few to whom knowledge was 

 more precious than gold. Dr. Albert Kellogg, the first resident ('alifornian botan- 

 ist, arrived at .Sacramento in \M9, and in 1850 Dr. II. II. Behr landed at .San 

 Francisco. These two i)hysicians became lifelong residents of the .State, and their 

 interest in science early divided their attention with their i)rofessional practice, 

 and led them to record the results of their studies in different journals. This, 

 too, was the time of many explorations and surveys undertaken by the general 

 government, which always included collections and observations on botany, duly 

 recorded in the published reports. While these various i)ublications are a mine 

 of wealth so far as they relate to the indigenous jilants, they are disappointing 

 when searched for information concerning the weed flora. They record few immi- 

 grant plants, except the most abundant of the mission introductions, already 

 broadspread over the land. Were one to judge from this negative evidence the 

 number' of introduced plants must have been very small at that time. But it is 

 probable that these botanists, like most collectors in new fields, gave their atten- 

 tion mainly to the many unfamiliar plants, whose novelty attracted them, to the 

 neglect of the common weeds they_ knew so well at home. 



THE RAILWAY PERIOD 



Of all the means by which weeds are disseminated railways easily rank the 

 first. The freight car carries its unbroken load from one end of the country to 

 the other; animals, grain, and goods of all kinds, instead of the limited movement 

 otherwise possible, are transported by rail wherever the market demands, regard- 

 less of distance. Population is increased, agriculture and commerce are stimu- 

 lated, resulting in a constantly augmenting traffic. Frequently the introduction of 

 a new weed can be directly traced to railway transportation, and its progress can 

 be followed by records of its appearance about railroad tracks or yards. Such is 

 the case with several now widely distributed weeds. 



For this period we enjoy definite records, beginning with Brewer & W'atson's 

 Botany of the Geological Survey (1876, 1880), down to the present day. Several 

 Floras have been published, covering different parts of the State, and many papers 

 have appeared in the botanical journals, so that there is now a considerable 

 knowledge of the composition of our flora. Information concerning immigrant 

 plans is embodied in these sources, and a few papers relate entirely to them. A 

 list of such papers will be found on a subsequent page. 



GEOGRAPHIC AND CLIMATIC LIMITS 



The area which this paper seeks to cover is that part of the State of California 

 south of Santa Barbara on the coast and Tehachipi Pass in the interior. But 

 while these limits have been observed as to the plants to be included, it has been 

 thought allowable to adopt a w^der horizon in the treatment of some of them. 



The physical configuration of this region, and its great climatic differences, 

 exert a determining influence not only on the indigenous flora, but on the exotic 

 as well. These restrictive conditions operate less rigorously on the introduced 

 weeds than on the native plants, enabling the foreigner, favored by the operations 

 of agriculture, to occupv places from which undisturbed natural conditions would 

 exclude it. It is for this reason that most immigrant plants are restricted to 

 the precincts of cultivation, only a few being able to overpass these limits. 



The great climatic areas into which Southern California is divided are three: 

 the desert, the mountain, and the region between the Sierra and the sea, usually 

 called the cismontane. 



THE DESERT 



The desert area, larger than the two others combined, is a land of parching 

 heat, violent winds and scanty and irregular rainfall. The soil in many parts is 

 of excellent character, but deficiency of water confines vegetation to such spe- 

 cialized plants as possess an adaptation to this rigorous environment. Up to a 

 recent time there was no cultivation, except at a few small oases, and it was only 

 there, and as a scanty and transient growth about mines and camping places, that 

 foreign plants could be found. Recent years have seen a change: towns, some 

 of them of considerable size, ha\-e sprung up along the railways which traverse the 

 deserts, and in every place where, by any means, water can be obtained for irri- 

 gation, lands of greater or less extent have been brought under the plow. 



