172 Evans: TAXONOMIC STUDY OF DUMORTIERA 
form thus agreeing essentially with D. irrigua, as described by 
Leitgeb. Soon afterwards Campbell (1, p. 49), in specimens of 
“D. trichocephala,’ from the Hawaiian Islands, found neither 
papilliform cells nor vestigial chambers. 
The descriptions of Leitgeb, Spruce, Goebel and Campbell 
thus record the following three types of surface in Dumortiera: 
(1) with both vestigial chambers and papilliform cells; (2) with 
vestigial chambers but without papilliform cells; (3) with neither 
vestigial chambers nor papilliform cells. When these types are 
clearly defined, as they sometimes are, they seem to yield excellent 
characters for the separation of species, although writers have 
expressed dissenting views regarding their value. Schiffner, for 
example, in his description of D. velutina (12, p. 26), emphasized 
the crowded papilliform cells as one of the features of the species, 
while Stephani claimed that such cells were present in all the 
species and that their persistence in D. velutina merely indicated a 
shaded environment. Coker (3, p. 226) explained the presence 
or absence of vestigial chambers in much the same way. In the 
vicinity of Chapel Hill, North Carolina, he found that plants of 
D. hirsuta growing in shaded, rather dry localities showed such 
chambers clearly, while plants in more exposed, wet localities 
were perfectly smooth; and he attributed these differences to 
environmental factors. Schiffner (14) criticized the views of 
Stephani and Coker. He maintained that the degree of develop- 
ment which the air chambers exhibited was not directly caused by 
the environment but that it depended upon inherited qualities. To 
support his statements he showed that “‘D. trichocephala”’ (with 
greatly reduced chambers) and D. velutina (with better-developed 
chambers and papilliform cells), often grew under exactly the same 
conditions in the primeval forests of Java and Sumatra and that 
both maintained their distinctive peculiarities. He showed 
further that plants of D. velutina from an almost dark well were 
exactly the same as those from sunny paths. His most convincing 
arguments, however, were drawn from plants which had been 
cultivated under identical conditions for about twenty years in 
the botanical garden at Prague. These plants represented D. 
velutina and D. irrigua, and their distinctive differences persisted 
unchanged. : 
