490 IOWA ACADEMY OF SCIENCE 



It secretes a substance that is decidedly objectionable. The 

 Amsickia intermedia and A. lycopsoides is most troublesome. 

 The aspect of a California field is entirely different than an 

 Iowa or an Illinois field. Broad acres are covered with the 

 Yellow Knapweed or Tocalote of the Mexicans (Centaurea 

 melitensis) and C. solstitialis are among the most troublesome 

 weeds of the meadows. In the Sacramento Valley and in the 

 foothills and valleys there is an abundance of the California 

 P°PPy (Eschscholtzia calif omica). The roadsides are covered 

 with one of the numerous species of Tarweed (Hemizonia luzu- 

 laefolia). The great Star Thistle (Silybum mariamim) and an- 

 nual grasses like Wild barley (Hordeum murinum) cover wide 

 stretches of the fertile fields. The two species of Prickly let- 

 tuce (Lactuca Scariola and the variety integrata) are common 

 everywhere in waste places. Certain weeds like the Greater 

 Ragweed (Ambrosia trifida) are missed entirely. The Foxtails 

 (Setaria glauca and S. viridis) are not common as with us. 

 Hilgard notes that S. glauca is a formidable weed in the foot- 

 hills of the Sierras and that Bromus mollis is a formidable weed. 

 The Russian thistle (Salsola Kali, var. tenui folia) is a common 

 weed. "White sweet clover (Melilotus alba) is common in places. 

 The Black medick (Medicago lupulina) and the Bur clover 

 (Medicago dentiadata) and Wild oats (Avena fatua) are com- 

 mon weeds. 



In the Feather river canyon at an altitude of 4,000 feet there 

 is comparatively little land that can be cultivated. In fields 

 and waste places in the vicinity of Portola the writer observed 

 Lactuca scariola and the var. integrata, Mayweed (Anthemis 

 Cotula,), Eschscholtzia calif omica var. tenuifolia; Sisymbrium 

 altissimum, Sisymbrium sp., Polygonum aviculare, Hordeum 

 jubatum, Sitanion elymoides, Achillea Millefolium, Gayophy- 

 tum sp., Hemizonia sp., Pteris aquilina, Bumex Acetosella and 

 Wyethia. This sunflower or rosin weed (Wyethia) of the open 

 meadows in the mountains occupies waste places in streets and 

 along roadsides. 



Near Belden, at an altitude of about 2,800 feet, the following 

 weedy plants were observed : Erigeron canadense, Common 

 mullein (Vcrbascum Thapsus), Anthemis Cotula, Cow herb 

 (Saponaria Vaccaria), Mexican tea (Chenopodium ambrosi- 

 oides), Russian thistle (Salsola Kali var. tenuifolia) , (Lactuca 



