140 Trans. Acad. Sci. of St. Louis. 



stem portion extends to considerable depth and is variously 

 branched. The new stems may come from rhizomes or from 

 the roots. Prairie or sandy soil. 



Pentstemon Cobaea, Nutt. A creeping rhizome which is a 

 crown rising obliquely to the surface, bearing numerous lateral 

 roots. Limestone hills. 



Pentstemon grandiftorus, Nutt. Base of stem decumbent, 

 throwing up offsets. Sand-hills. 



Ruellia ciliosa, Pursh. Small crown with a fascicle of 

 fibrous roots. Prairie. 



Dianthera Americana, L. Extensive creeping white 

 rhizomes about the size of the vegetative stems, rooting at 

 the nodes. The lower part of the stem roots at the nodes 

 and persists. The vegetative stems are thus a continuation 

 of the upturned ends of the rhizomes. In water or very wet 

 places. 



Verbena ur time folia, L. Tap-root with small crown. Low 

 ground. 



Verbena haslata, L. Tap-root with strong crown. Low 

 ground. 



Verbena striata, Vent. A tap-root supporting a crown. 

 Prairie. 



Lippia lanceolata, Michx. Extensively creeping inter- 

 twining rhizomes similar to the vegetative stems, rooting at 

 the nodes. Wet places. 



Teucrium Canadense, L. Creeping rhizomes with distinct 



dorsiventrally flattened internodes. Thickets and moist places. 



Lycopus sinuatus, Ell. Creeping rhizomes with distinct 



internodes rising obliquely into the vegetative stem. Rooting 



at nodes. Wet places. 



Pycnanthemum mulicum, Pers. var. pilosum, Gray. Short 

 rhizomes which soon become erect, thus producing stems in 

 clusters. Springy bogs. 



Salvia azurea, Lam. var. grandifiora. Benth. A strong 

 crown with woody roots. Prairie. 



Monarda Jistulosa, L. Slender brown woody rhizomes, 

 extensively interlacing. Thickets and open woods. 



Lophanthus nepetoides, Benth. A crown with numerous 

 fibrous roots. Woods. 



