Two Irish Brown Algae: Pogotrichum 
and Litosiphon, 
BY 
T. JOHNSON, 
Professor of Botany, Royal College of Science, Dublin „ 
With Plate XXIV, 
URING an algological visit to the west coast of Clare 
JLy in September, 1891, I found growing on the Kilkee 
rocks at low water, plants of Alaria esculenta , Grev., covered 
with brown tufts of fertile filaments looking very much like 
Litosiphon Laminariae , Harv. Professor Reinke of Kiel, to 
whom I sent material, concluded it was not this species, 
though very near to it, but a second and new species of the 
genus Pogotrichum of which he was then describing the type, 
P. filiforme , received from Heligoland. The Kilkee plant 
was accordingly, after examination and comparison, named 
Pogotrichum hibernicum. Reinke’s diagnosis of Pogotrichum 1 
is as follows : — 
‘ Unverzweigte, buschelformig beisammenstehende, faden- 
formige Thallome von radiar gebautem Querschnitt und inter- 
calarem Wachsthum. Vegetations-Faden aus mehreren oder, 
1 J. Reinke, Atlas deutscher M. Alg., II, 3-5, s. 6r, Tf. 41, Fig. 13-25. 
[Annals of Botany, Vol. VIII. No. XXXII. December, 1894.] 
