spermum picroides (Compositae) is a widespread and well known 

 weed in the Mediterranean region. Plants were first recorded in 

 North America from a small colony that had become established 

 near the Engineering Building on the Berkeley campus of the Uni- 

 versity of California in 1915. A recent visit to this site revealed 

 plants still growing in this area of initial introduction, but this 

 species apparently has not succeeded in spreading from its small 

 foothold in the New World, since it is otherwise unknown in 

 California or elsewhere in the U.S. In contrast, however, some 

 species which are well behaved in their homeland may become 

 widespread and sometimes aggressive weeds in their new home. 

 For example, a relative of the filMee^Erodium obtusiplicatum 

 (Geraniaceae), is a rare plant in northwestern Africa, yet is cer- 

 tainly one of the commonest plants in California. Gorse {Ulex 

 europaeus, Leguminosae) is a relatively well behaved shrub in 

 its native Europe, but has become a troublesome weed from cen- 

 tral California northward into southern Oregon. Gorse burns 

 very easily and rapidly, and as a consequence is a considerable 

 fire hazard in areas where it has become established. In the 

 1930's much of the town of Bandon in southern Oregon was 

 destroyed by a fire whose destructiveness was due to the large 

 areas of land in and around the town that were (and still are) 

 covered by Gorse. 



Most weedy species that occur in California are of exotic ori- 

 gin, although a few native species have also developed weedy 

 tendencies. For example, the fall- and winter-flowering Telegraph 

 Weed (Heterotheca grandiflora, Compositae) is a native species 

 that probably originated as an inhabitant of sandy soils in 

 southern California. In recent years this species has spread north- 

 ward into central and northern California, where it is now com- 

 mon along roadsides or in sandy fields. Another weedy Compos- 

 ite is Pineapple Weed (Matricaria matricarioides), an extremely 

 common annual weed of waste places in the west which un- 

 doubtedly was originally native to the area, although its natural 

 range is unknown since it is so widely spread as a weed of dis- 

 turbed habitats. Another genus which has been successful in 

 spawning weeds is the fiddleneck genus Amsinckia (Boragin- 

 aceae) which is a roadside and grassland weed over much of 

 California. 



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