Hitchcock — Studies on Subterranean Organs. 7 



Iva ciliata, Willd. Annual. Moist ground. 

 /. xanthiifoUa, Nutt. Annual. Open low ground. 

 Ambrosia trifida, L. Annual. Low ground. 

 A. artemisiae folia , L. Annual. Cultivated soil and waste 

 places. 



A. psilostachya, DC. Buds on creeping roots. Prairie, 

 open woods and sandy soil. 



Xanthium Canadense^ Mill. Annual. A weed in cultivated 

 soil. 



Eclipta alba, Hassk. Annual. Near river banks and other 

 wet places. 



Heliopsis scabra, Dunal. Small crown with numerous 

 fibrous roots. Borders of woods. 



Echinacea angustifoUa, DC. Crown branched, supported 

 by a strong root. Stony bluffs and less frequently on prairie. 



Lepachys pinnata, T. & G. Crown of numerous stems but 

 no long root. Many rosettes are thrown up from this crown 

 which probably produce flowering stems the second year. 

 Borders of woods. 



L, columnaris, T. & G. Crown supported by a long tap- 

 root. Prairie. 



Helianthus annuus, L. Annual. Fields and open ground. 



H, petiolaris, Nutt. Annual. Sandy soil. 



H. rigidtis, Desf . Khizomes. Prairie. 



H, grosse-serratus, Mart. Rhizomes. Moist places. 



H. Maximiliani, Schrad. Rhizomes shorter and thicker 

 than the preceding. Stony hills and prairie. 



H, hirautuSf Raf . Rhizomes. Dry open woods. 



H. tuberosus, L. Rhizomes ending in tubers. Woods, 

 fence-rows and low ground. 



Aclinomeris squarrosa, Nutt. Crown of short rhizomes 

 or the horizontal bases of the stems. Woods. 



Coreopsis involucrata, Nutt. Annual. Springy places. 



Bidens frondosa, L. Annual. Fields and low ground. 



B, connata, Muhl., B. cernua, L., B, chrysanthemoides, 

 Michx. Annual. Wet places. 



Hymenopappus corymbosus, T. & G. Crown single. New 

 rosettes come from the axils of the old leaves, thus broadening 

 the crown. Stony hills. 



