PAPERS ON BOTANY 257 
In group three, the spots of alga are epiphyllous, 4-8 mm. 
in diameter, the brownish-green color. They are compact 
with regular margins and have a feathery appearance due to 
the very long fruiting stalks. There are from one to ten spots 
on nearly every one of the three hundred leaves in the collec- 
tion. To this group belongs specimens on Ocotea leucoxylon 
(Sw.) 7393, Mayaguez, Inga laurania (Sw.), Willd., 7023, 
Jajome Alto and Coccolobis diversifolia 8877, Maricao. 
Group four shows the alga forming spots which are epiphyl- 
lous, averaging 4 mm. in diameter, and very scattered. These 
spots are flat and smooth with very few fruiting stalks. They 
are light in color, and are more or less regular in outline, Of 
this type are specimens on Acrodilidium salicifolium, 7360 
Hormigueros, Nectandra patens, (Sw.) Griseb, 1750, Jambosa 
vulgaris P. 8743, Afiasco, Artocarpus incisa L., 7196. To this 
group also belongs the alga on Sergania 2242, Cabo Rajo, ex- 
cept that the spots in this case are only 1-2 mm. in diameter 
and are very irregular in outline. 
In general it may be said that the algal spots are composed 
almost entirely of fruiting stalks. The differences in the re- 
sisting power of the several hosts are the causes of the varia- 
tions in luxuriance and gross details. 
1. D. D. Cunningham, Trans. Linn. Soc., 2nd. ser., Bot., 1: 301-318, 
2. H. Marshall Ward, Trans. Linn., Soc., 2nd. ser., Bot., 11: 87-115, 
3. N. Thomas, Ann. Bot., 27: 781-793, 1913. 
4. Esther Young, Myc., 7:143-150, 1915. 
5. Dr. W. G. Farlow, Copy of letter under date May 14, 1916. “The 
growth which you send on guava is a Cephaleuros, a genus of alga which 
is often associated with lichens of the genus Strigula. Your material is 
the pure algal form without admixture of lichen hyphae. It seems to be 
the same as the Cephaleuros mycoidea G. Karsten, on guava leaves dis- 
tributed in Wittroch & Nordstedt’s Algae Aquae Dulcis, No. 413, from 
Jamaica. I have also the same species from Jamaica, from another source. 
Although the specimens in Wittroch & Nordstedt were named by W., 
Schmidle, he stated in Hedwigia XXXVII, 62, 1819, that he considered it 
uncertain whether the form on guava really belonged to C. mycoidea, but 
at the same time did not refer it to any other species. 
“The C. mycoidea Karsten, is the same as Mycoidea parasitica D, Cun- 
ningham, which is considered ‘by Marshall Ward and Harriot to be iden- 
tical with the older Cephaleuros virescens Kunze. The Jamaica alga on 
guava may be kept under the latter name for the time being. The species 
of Cephaleuros which have been described, although not numerous, are by 
