256 ILLINOIS ACADEMY OF SCIENCE 
NOTES ON CEPHALEUROS VIRESCENS 
RutuH Hictey, UNIVERSITY OF ILLINOIS 
Cephaleuros virescens, an alga belonging to the family, 
Chrolepideae, is rare as a parasite, occurring only in a few 
rather restricted regions. It has hitherto been recorded on 
very small number of hosts, and the literature on the subject 
is very scant. The more important papers dealing with the 
genus Cephaleuros, are those by D. D, Cunningham’, H. Mar- 
shall Ward’, and N. Thomas’. The last paper deals with speci- 
mens of the alga on plants in Ceylon, The Barbados, and the 
Dutch East Indies, where it causes much damage, on account 
of its weakening effect on young tea plants. 
In view of the meager data available in regard to a form 
of economic importance it seems wise to list and briefly de- 
scribe material found on the Porto Rican collection made by 
Prof. F. L. Stevens during the summer of 1915. This collec- 
tion was described by Miss Esther Young’. A specimen of 
the alga in question, growing on Psidium, was determined by 
Dr. W. G. Farlow’, and his letter, giving a brief discussion of 
the species, is quoted in full below. The other determinations 
were made by me. The Cephaleuros appears on some ten differ- 
ent hosts, superficial characters making it possible to divide the 
form into four distinct groups. It is with these gross details 
that this paper is concerned. 
In group one, the alga is hypophyllous, forming a spot 8-10 
mm, in diameter. The fruiting stalks are large and very green 
even when dry, are more or less diffuse, but occur only in the 
central portion of the spot. The outside uncovered zone is 
dark, a little discolored, and shows through to the upper side 
as a dull brownish-green. There are not more than three or 
four spots on a single leaf. To this group belong specimens 
on Lomidesia lindiniana Berg., 8380, Jajome Alto, and Cu- 
pania americana. L., 9144. 
In group two, the fruiting spots are epiphyllous, 1-6 mm. 
ir diameter, and very numerous. They are solid, very com- 
pact with definite margins, greenish-gray in color, and appear 
as a dark spot on the under side of the leaf. This is the con- 
dition on Miconia laevigata (L) P. 7373, Mayaguez. 
