MICHIGAN ACADEMY OF SCIENCE. 131 



*508. Senecio discoideus (Hook.) Britton. Wheeler. 



509. Senecio Balsamitae Muhl. Ragwort. Rock shore crevices; bare 

 burned ridges; burn forest. 



510. Arctium minus Bernh. Burdock. Clearmgs. 



511. Cirsium arvense (L.) Scop. Canada Thistle. Clearings. 



512. Taraxacum officinale Weber. Dandelion. Rock shore crevices, bare 

 burned ridges, and clearings. 



513. Lactuca canadensis L. Wild Lettuce. 



514. Lactuca pulchella (Pursh.) DC. Clearings and bare burned ridges. 



515. Lactuca villosa Jacq. Clearing: Park Place. 



516. Prenanthes racemosa Michx. Rattlesnake-root. Rock shore cre- 

 vices and margins of rock pools; sand beaches. 



517. Prenanthes alba L. 



518. Hieracium scabrum Michx. Hawkweed. 



519. Hieracium umbellatum L. Rock shore crevices, bare burned ridges, 

 and burn forest. 



