Hitchcock — Studies on Subterranean Organs. 133 



purascens, and Agrimonia mollis. The familiar Polygonatum 

 giganteum is the typical form of this. The upper part of the 

 oblique caudex is drawn down into a horizontal position each 

 successive year by the contraction of the lateral roots. At 

 first the oblique crown and the oblique caudex may seem to 

 resemble each other. The oblique crown is surmounted by 

 the dead base of a vegetative stem or else, where offsets are 

 produced which soon become independent, the old stem dis- 

 appears. But the oblique or slowly creeping horizontal 

 rhizome ends in a terminal bud which continues the growth. 

 The vegetative stems are thus axillary from the rhizome. 



The creeping rhizome may show peculiarities, as in Teu- 

 crium Caiiadense, where it is dorsiventrally flattened and con- 

 stricted at the nodes. In Scutellaria parvula the internodes, 

 or some of them, swell up into so-called tubers, forming a more 

 or less interrupted chain, " subterranean stolons moniliform- 

 tuberiferous," Gray. In Apios tuberosa genuine tubers are 

 formed though they are not usually terminal on a rhizome as 

 is the common potato, but there may be several on one 

 rhizome. These tubers may send out new rhizomes or may 

 become a crown and send up successive vegetative shoots. 

 Glycyrrhiza lepidota produces deep root-like rhizomes which 

 may grow several or many feet before producing a new plant. 

 Each new plant becomes a strong crown. One would scarcely 

 suspect the presence of rhizomes in this case. 



Comandra pallida propagates in a similar manner but the 

 crowns are closer together. Astragalus Plattensis is also 

 similar but the new plant forms a small fleshy root below and 

 sends a stem to the surface which becomes a small or slender 

 crown. Ipomoea leptophylla, a very peculiar case, was 

 described in the Botanical Gazette, 25:52. This plant 

 forms a very large fleshy root, the summit of which is sunken 

 several inches below the surface. A crown is formed but in 

 addition it propagates by slender roots about the size of a 

 fence wire which have their origin along the lower half of the 

 root and rise obliquely to near the surface when the new plant 

 is formed several feet from the parent. In some plants the 

 creeping decumbent bases of the vegetative shoots branch and 

 root abundantly, forming a tangled mass of stems which per- 



