84 MISSOURL BOTANICAL GARDEN. 
collections of Masson, Aiton described a number of Azorean 
species. Our present knowledge of the subject comes 
largely from the work of Guthnick, the two Hochstetters 
and Seubert, H. C. Watson, Drouet, Godman, and the 
naturalists of the Challenger Expedition. In the contribu- 
tions published by these men are to be found sufficient 
references to minor papers.* Just as Seubert’s Flora 
Azorica will always form a necessary starting point for 
students of the flora of these islands, Watson’s account 
of the flora in Godman’s Azores marks a point at 
which most of the critical difficulties were pointed out 
and the list of Azorean plants brought to a fair degree 
of accuracy by the elimination of double entries and 
synonyms. 
As Mr. Watson has shown (1. ¢., page 262), it is not 
probable that future collectors will add any considerable 
number of species to the phanerogams and pteridophytes of 
the Azores, though a few which have escaped detection thus 
far because of seasonal or geographical restriction, occa- 
sional new introductions, and species heretofore mistaken 
for others or forming part of ultimately divisible aggre- 
gates, willslightly augment the list from time to time. Even 
with the bryophytes, which M. Cardot believes can easily be 
doubled, the absolute increase in species is not likely to be 
at all considerable. With thallophytes, however, the case 
is quite different. Though perhaps relatively few addi- 
tions to the lichens will be made, the fungi are practically 
unstudied, and in moist wooded regions many species should 
be found; and the marine algal flora, though unquestionably 
small, may doubtless be increased considerably by collec- 
tions prosecuted through the entire year, while there is 
reason to expect a very large number of diatoms and des- 
mids, as well as many representatives of other groups of 
fresh-water algae, whenever careful collections shall have 
* Such of their works as are referred to in the catalogue of plants, 
appear in a list appended to the catalogue. 
