456 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



Stemmed are those with the main stem below the inflorescence 

 less than 6-10 inches long and generally shorter than the mature 

 umbel. The later flowering begins, the longer the stem. 



The third column includes under ''pubescence o" plants with- 

 out hairs outside the involucre or so rare that they cannot be 

 found without some search. Under "pubescence — " are those 

 essentially glabrous, but with hairs easily found on some parts. 

 The ± and + indicate pubescence medium or abundant. The 

 hairiness seems to vary largely with some external condition, 

 plants being sometimes glabrous below and hairy above, some- 

 times the opposite. 



The leaf- form column includes under I, leaves broadest below 

 the middle; under II, leaves broadest at the middle; and under 

 III, leaves broadest above the middle. 



The subdivisions have been carried out further on leaf width, 

 red color of herbage, width of appendage, length of petiole, angle 

 of divergence of hairs, length and thickness of peduncle, number 

 of times the inflorescence branches, etc. It was found, however, 

 that a number of these characters and others that have been used 

 in separating species are dependent entirely on the stage of 

 development. A thorough study of the southern species in both 

 early and late stages will be necessary before they can be accurately 

 classified, so I have not included specimens from south of Mary- 

 land, though I have listed a few western plants for comparison. 

 Plants of T. arundelana at the time of first blooming and in mid- 

 summer would hardly be recognized as the same species. 



The amount of red color in stems and leaves, although it varies 

 somewhat with the environment, is unquestionably largely gov- 

 erned by hereditary factors. 



I have classified about 200 distinguishable forms but for lack 

 of space can only show the more easily recognized kinds on the 

 diagram.* 



The numbers following each minor subdivision show the num- 

 ber of plants in the respective group indicated by the associated 

 letter as follows: 



A. Plants from the type locality of T. arundelana. 



B. Type of T. arundelana. 



C. Plants with very narrow appendages but broader than the 

 usual T. Ipecacuanhae type. 



