288 MR. A. D. COTTON ON 
On some Endophytie Alge. By A. D. Covton, F.L.S., Assistant, 
Herbarium, Royal Botanic Gardens, Kew. 
[Read 18th January, 1906.] 
(PLATE 12.) 
Spectes of Endophytie Alge are found amongst several genera 
belonging both to the Pheophycea and to the Chlorophyces. 
All are microscopic forms the thallus of which is represented 
either by filaments or plates of cells which grow in the tissues 
of larger Algæ. In some cases the endophyte is found in the 
gelatinous walls of the external surface of the host-plant; in 
others, the filuments penetrate deeper into the host and are 
found running between the cells of the thallus-tissue. In 
neither case is the invading plant necessarily parasitic. 
The genus Endoderma among the greens and Streblonema 
among the browns may be taken as representatives of Endophytic 
Alge from these two groups. In Endoderma the entire life- 
history of the plant is (with a few exeeptions) endophytie, save 
for a few colourless hairs and the liberated zoospores. But in 
Streblonema, though the main mass of tissue is within the host- 
plant, the reproductive portion is always produced outside. 
Huber’s researches on the former and Sauvageau’s on the latter 
have added much to our knowledge of this group of plants. 
The object of the present paper is to record some observations 
on the life-history of Endoderma virida (Rke.), Lagerh. Two 
species of Streblonema are also dealt with. 
As to material, fresh alge were examined when possible, 
but specimens preserved in formalin yielded very good results. 
As recorded later, Endoderma viride was found abundantly in 
the tissues of Nitophyllum Hillie. This latter plant is a deep- 
water alga and is never found exposed, consequently it had to be 
obtained by means of dredging. During spring-tides it may 
occasionally be found on the steep surfaces of rocks just below 
low-water mark. It is also sometimes thrown up after a storm, 
and such specimens though torn and imperfect are quite fit 
material for the examination of Endoderma, as the endophyte is 
protected within the tissues. 
The bulk of the material was obtained by dredging; and here 
the writer would like to express his best thanks to Dr. E. J. 
Allen for his kindness in giving him opportunities for dredging, 
