BRITTON: FLORA OF THE VIRGIN ISLANDS 109 
D. W. Marble 76; hills north of Charlotte Amalia, 409; on the ground, 
Magin’s Bay to Mafolie, 7372. 
21. ANTHOCEROS PUNCTATUS L. 
St. THOMAS: in a mud hole, Crown, 450 m. alt., 1363. 
REPORT ON THE LICHENS OF ST. THOMAS AND 
ST. JAN’ 
The following report is based primarily upon a study of 90 numbers 
of lichens from St. Thomas and St. Jan Islands; from St. Thomas, 
82 numbers collected by Dr. N. L. Britton, Mrs. E. G. Britton, and 
Miss Delia W. Marble, unless otherwise stated; from St. John, 8 
numbers collected by Dr. N. L. Britton and Dr. J. A. Shafer. To 
these have been added a few species recorded by Nylander in Flora 
(63: 127. 1880) and two endemic species described by Mueller- 
Argau. Altogether, we have represented 30 genera with 69 species 
and varieties, of which three species 4nd one variety are here de- 
scribed as new. The discussion of the characteristics of the lichen- 
flora will be confined to that of St. Thomas. 
There is no peculiar element in the lichen-flora of St. Thomas 
comparable with the gelatinous rock-lichens of Mona Island (see 
Annals Missouri Bot. Gard. 2: 35. 1915), or with the crustose and 
gelatinous rock-lichens of Bermuda (see Bull. Torrey Bot. Club 43: 
146-155. 1916). Such rock-lichens as occur on St. Thomas belong 
to widely distributed groups even where the actual species are more 
restricted in distribution. In fact the greater part of the lichen- 
flora is made up of species more or less common throughout the West 
Indies or even in the tropics of both hemispheres. It is probably safe 
to say that there are not more than half a dozen endemic species in 
St. Thomas. Of the three new species described in this paper, two 
occur elsewhere in the West Indies. The flora is comparatively rich 
in the variety of crustose bark-lichens, especially in the genera An- 
thracothecium with 5 species, Arthonia with 8 species, and Opegrapha 
with 5 species. It is rather surprising that only one Graphis and no 
Trypethelium should have been collected. On the whole the lichen- 
flora is rather commonplace. In the following list, stations outside 
of the Virgin Islands are noted for species, the range of which is 
limited or not well known. 
LICHENS OF ST. THOMAS 
1. DERMATOCARPON HEPATICUM (Ach.) Th. Fr. On soil, without 
definite locality, 151. 
16 Contributed by Lincoln W. Riddle, Wellesley College. 
