Tgr8}] PFEIFFER—THISMIA 247 
tically only the method of pollination and fertilization where this 
process occurs. This has been reported by several workers: MIERS 
(9) in Dictyostegia orobanchioides, WARMING on Brazilian forms and 
in A pleria lilacina, and ErNst and BERNARD in Burmannia candida 
and B. Championii. In all these forms germination of pollen 
occurs in the pollen sacs, so that the tufts or bundles of pollen tubes 
issue from the anthers and penetrate the:stigma. Mzrers remarked 
that the identity of these pollen tubes is clear with the use of a 
common lens, while the cottony mass of threads is evident, sup- 
posedly to the naked eye. He distinctly stated that this is not 
true, however, in Myostoma and Ophiomeris (9), and took this as 
evidence, in his early time, that thereby ‘‘the theory of the appli- 
cation of pollen tubes for the fertilization of its ovules is distinctly 
disproved.”” Ernst and BERNARD were unable to discover this 
method of pollination in Thismia javanica or T. clandestina, although 
aware of its presence in other.forms and so alert for indications here. 
So far the evidence goes to show that such early germination of 
pollen and subsequent growth occur only in Euburmanniae, where 
the structure of the flower is different from that in Thismia. There 
seems to be a general conclusion, however, that forms are self- 
pollinated, through evidence such as given by SCHLECHTER in 
Thismia Winkleri (1, 11), where little diptera were found in the base 
of the flower where the pollen must fall. 
Investigation 
The material upon which the present study is based is that of 
Thismia americana, collected by the writer in Chicago, Illinois, dur- 
ing the summers of 1913 and 1914. The relationships of this form 
and a description of its structure, etc., were given in a previous 
paper (10). 
In very young stages the stamen set appears to be distinct 
earlier than the ovary parts. Each stamen, of which there are 6, 
produces the usual 4 microsporangia, all of which are directed away 
from the central axis of the flower. Thus the surface of the anther 
toward the center is quite flat or slightly concave, while the oppo- 
site one is marked by the 4 lobes, in 2 pairs, which represent 
the rudiments of the microsporangia. At this stage usually the 
