96 
BIBLIOGRAPHY. 
resembles Spermotliamnion flahellatum, from which, however, it is 
sharply separated by the tetraspores, being replaced by large 
globular sporangia, containing a large number of spores, even as 
many as 60. 
Antithamnion pteroton , Bornet. — A very small species, resembling 
C. pluma and elegans , but more delicate, and of a more distinctly 
rose colour. It is easily distinguished from either of these, how- 
ever, by its pinnules when well developed being pectinate, and by 
its cruciate tetraspores. 
Revision von Jurgen's Algce Aquaticce. By Th. Reinbold. (“ Nuova 
Notarisia.”) 
Major Reinbold has performed a much-needed and useful work 
in revising Jurgen’s “ Algae Aquaticae.” This collection of exsic- 
cata was published between the years 1818 and 1824, consequently 
the nomenclature used by the author is very different from that at 
present in use, but no very startling results have been attained by 
this revision. Major Reinbold, however, considers that Merten’s 
Conferva torta , specimens of which are contained in Jurgen’s collec- 
tion, are identical with Enteromorpha percursa , Harv., and var. y of 
J. Agardh’s species of the same name. He has consequently renamed 
this species Enteromorpha torta , and at the end of his paper gives 
a long and interesting account of its synonymy. 
LICHENES. 
M, P. Hariot (Bull. Soc. Myc., France, vii., p. 32) has shown 
that the genus Dictyonema is a true lichen. The fungal element 
belongs to the Hypochnaceae, and nearest to the genus Coniophora , 
its basidia bearing four spores ; the alga is a species of Scytonema. 
The species of Dictyonema resemble those of Stereum in habit ; 
the inferior surface when fully evolved consists of a continuous 
layer of basidia — hymenium — the upper surface being of a spongy 
texture and green colour. 
Dictyonema sericeum, Johow., has been collected in Scotland and 
Wales, and is figured in Eng. Bot., pi. 2954, as Rhizonema inter- 
ruptum (Carm.), Thwaites, and reproduced in Cooke’s “ British 
Fresh-Water Algae” as Scytonema interruptum, Thw. 
