Hitchcock — Studies on Subterranean Organs. 5 



short that the plants appear in bunches. Artemisia Ludovi- 

 ciana grows naore or less in sandy soil. 



Propagation from running roots. A few species form 

 adventitious buds upon creeping propagating roots. These 

 are Ambrosia psilostachy a, Onicus undulatus and Lygodestnia 

 juncea. It is well known that Taraxacum officinale produces 

 buds upon the cut roots although they do not ordinarily form 

 spontaneously, and some of the other crown forming species 

 may also have this power. This has not been investigated. 

 All the three species mentioned above are prairie xerophytes 

 though Ambrosia is also frequent in sandy soil. Onicus pro- 

 duces tuberous roots and the buds may be formed on these or 

 on the slender roots. 



Before drawing conclusions as to the relation between the 

 structure of the subterranean organs and the environment of 

 the plant other groups must be investigated. 



Below is given a reference list of our Compositae, with 

 brief notes on subterranean parts, arranged according to 

 Gray's manual. 



Vernonia Baldwinii, Torr. A crown of short knotty tan- 

 gled rhizomes. Prairie and more or less in moist open soil. 



F. fasciculata, Michx. Similar to above. Low ground. 



Eupatorium altissimum, L. Close crown with buds along 

 base of old stems. Along edge of woods, hedges, on prairie 

 and often on rocky soil. 



E. perfoUatum, L. Crown a creeping horizontal rhizome 

 with branches. Wet places. 



E. ageratoides, L. Crown small with numerous fibrous 

 roots, easily separating into parts. Woods. 



Kuhnia eupatorioides, L. Crown supported by a long tap- 

 root. Prairie and stony bluffs. 



Liatris squarrosa, Willd. Crown from a corm-like woody 

 globose root. Sandy soil. 



L. punctata, Yiook. Root similar. Prairie. 



L. scariosa, Willd. Root similar. Prairie and stony bluffs. 



L. pycnostachya, Michx. Root similar. Base of stems 

 fibrous-coated. Moist prairie, 



Solidago Lindheimeriana , Scheele. Short rhizomes. 

 Open woods and wooded stony bluffs. 



