JoHnson—Pogotrichum hibernicum. 3 
which a parasitic hypha had entered. A close examination of the 
sections gives every indication that these endophytic or intra- 
cortical hyphe can, after creeping for some distance in the Alaria 
thallus, emerge at either surface to form new Pogotrichum tufts. 
This vegetative reproduction by means of stoloniferous endophytic 
hyphae, though distinctly novel in a brown alga, is not uncommon 
in parasitic Phanerogams (e. g. Arceuthobium,' Pilostyles”), in 
which plants their intra-cortical hyphae give rise to new plants 
at the external surface of their host-plants. Having been familiar 
for some time with the budding of the intra-cortical hyphae in 
Arceuthobium and other parasitic Phanerogams, it was not un- 
natural for me to see in the intra-cortical hyphee of Pogotrichum 
a similar power of vegetative reproduction. My views were very 
much strengthened on reading a noteworthy paper by M. C. 
Sauvageau, which, under the title “Sur quelques algues phéos- 
porées parasites,’ has appeared this year® in the “Journal de 
Botanique.” In this paper the few observations hitherto recorded 
of parasitic brown algze possessed of endophytic hyphe are 
summarised, and the interesting statement is made that the late 
Professor Harvey, of Trinity College, Dublin, was the first to 
record, in 1846, the penetration into the thallus of the host-plant 
by the filaments of a parasitic brown alga.* In 1850 and 1851 
Thuret observed Streblonema investiens, Thur., sending endophytic 
filaments into the thallus of Gracilaria compressa, an observation 
repeated by Hauck in 1875. In 1872 Kny, at Heligoland, 
observed the endophytic filaments of an unidentified sterile brown 
alga in the thallus of Delesseria sanguinea, Chondrus crispus, 
Laminaria saccharina, &e. In 1875 Reinsch founded the genus 
Entonema, to include those microscopic Hetocarpee which grow 
parasitically on other Pheophycee, and on Rhodophycee, and 
send endophytic filaments into their thalli. In 1878 the most 
17. Johnson, ‘“‘ Annals of Botany,”’ 11. 
2 Solms Laubach, Das Haustorium d. Loranthaceen, &c., in Pringsheim’s Jahrb. v1. 
3C. Sauvageau, Journ. de Bot., Nos. 1-7, 1892. 
4W. H. Harvey, Phyc. Brit., 1846-1851, Pl. 28, B. (The basal joints of the fila- 
ments of Elachista velutina, Aresch: (Ectocarpus velutinus, Kiitz.), are represented 
penetrated into the thallus of Himanthalia Lorea, Lyngb.) Hlachista attenuata, Hary. 
(Uyriactis pulvinata, Kitz) is, more strictly speaking, the first brown alga figured 
(op. cit. Pl. xxvir., A.) and described as truly parasitic. ae 
