Clausen, Robert Theodore <br/><br/>
Sedum of the trans-mexican volcanic belt :  an exposition of taxonomic methods / 
by Robert T. Clausen; drawings by Elfriede Abbe 
 - Ithaca :  Comstock Publishing Associates,  1959 
 - x, 380 p. :  ill., maps ;  24 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Sedum