Table 4. Species on which dried tissue tests were performed, and sites where samples were taken.

sample	species	location	soil sample	notes
5001	Malva sylvestris mallow	Willow & 16th	28
5002a	Helminthotheca echioides bristly ox tongue	Willow & 16th	28
5002b	Helminthotheca echioides bristly ox tongue (different population)	Willow & 16th		in asphalt
5003	Hypochaeris radicata cat’s ear	Willow between 16th & 17th	28
5004	Plantago lanceolata English plantain	Willow & 17th	29
5005	Lactuca ludoviciana wild lettuce	Willow & 17th	29
5006	Trophaleum majus nasturtium	Willow & 15th		in asphalt
5007	Taraxacum officinale dandelion	Willow & 15th		in asphalt
5009	Foeniculum vulgare sweet fennel	Wood & 15th		in asphalt

All samples were collected on 12 May 2015 in Oakland, CA. Tissue samples were rinsed with tap water, then dried in botanical voucher sample driers at the University and Jepson Herbaria, University of California, Berkeley, before being sent for testing at Brookside Laboratories. Sample numbers refer to voucher specimens in the University and Jepson Herbaria, submitted by Prof. T. Carlson; the full reference for the first sample is, e.g., “Thomas Carlson 5001.”