SOME BRITISH SPECIES OF PHJSOPHYCEiE 371 



under that name by Kylin. The plant is allied to H. maculans 

 Sauv., but is distinctly smaller. Notwithstanding the well-known 

 variability of form exhibited by the algae of this genus, the author 

 is inclined to agree with Kylin in regarding the species as distinct, 

 and Hecatonema as the best genus in which to place it. 



Additional evidence confirming the latter point w r as afforded by 

 a fragment of Bhodijrnenia, which bore some later stages of the 

 epiphyte. From each of these older plants grew a tuft of Ecto- 

 carpus-like filaments of about 1 mm. in length. The filaments 

 gave rise to a few short subulate branches, but no sporangia were 

 observed. The cells in the middle and upper parts of the filaments 

 measure 20-30 x 12 /x, though towards the basal region they are 

 scarcely longer than broad. 



There is a remote possibility that the above-mentioned fila- 

 ments may represent the grow r th of young Ectocarpus plants that 

 had germinated in the centre of the Hecatonema tufts. A careful 

 examination did not yield any evidence to support such a view, 

 though to decisively demonstrate organic connection between the 

 two types of algae is not easy. There is, however, every appear- 

 ance of such a connection, and this, taken together with the fact 

 that such filaments are present in the allied species H. maculans, 

 make it highly probable. In H. maculans the upright filaments 

 give rise to sporangia, and there is no reason to doubt the pro- 

 duction of similar sporangia in H. diffusum if sufficiently late 

 stages could be discovered. 



Ectocarpus PADiNiE Sauv., Ann. des Sci. Nat. ser. 8, tome ii. 

 1896, p. 268 ; Journ. de Bot. vol. xi. 1897, p. 24 ; Giffordia Padina 

 Buffham, Grevillea, vol. xxi. 1893, p. 88, tab. 185, figs. 5-7. 



The present notes on this plant are confined to the vegetative 

 characters. Material was obtained from specimens of Padina 

 Pavonia collected at Torquay (August, 1905 and 1906). 



The remarks made by Sauvageau (Journ. de Bot.) as to habit 

 have been fully confirmed ; the plant is truly endophytic, the fila- 

 ments, which are intercellular, growing in the direction of the lon^ 

 axis of the Padina. In a section of the latter two entirely diffe- 

 rent aspects of Ectocarpus Padina are thus obtained, depending 

 on whether the section be transverse or longitudinal. In the 

 transverse section Ectocarpus Padina is very inconspicuous, only 

 the transversely cut ends of the filaments being visible, whilst in 

 the longitudinal section its endophytic character is at once appa- 

 rent ; there is little doubt that it was through not examining a 

 longitudinal section that Buffham failed to recognize the true 

 habit of the plant. Drawings made by the writer of the somewhat 

 remarkable endophytic filaments possessed by this species agree 

 in every way with those given in the Journ. de Bot. 1897 ; the 

 curious foldings in the walls noticed by Sauvageau were also very 

 marked in the Torquay material. 



Antheridia and plurilocular sporangia occurred plentifully, but 

 experiments have not so far been conducted with regard to fertili- 

 zation. Two types of sporangia, as have been described by 



2 e 2 



