11 



Fig. no Durvillea antarctica. A-E, young plants ( x if), F, dia- 

 gram of tissues, black = secondary cortex ; dots = unswoUen hyphae ; 

 plain = medulla. G-I, stages in swelling of longitudinal hyphae 

 (G, H x26o; I X i6o). J. R.L.S. of meristoderm and cortex 

 (hy=hypha) ( x 170). K, oogonium L, M, oogonium liberating 



ova ( X 180). (After Naylor.) 



possesses very much the appearance of a Laminaria. This applies 

 to all four species (five if one includes Sarcophycus potatorum of 

 Tasmania). The large solid stipe arises from a scutate holdfast and 

 very soon passes into a flat, expanded, fan-shaped lamina, which 

 later becomes spUt into segments although no definite appendages 

 are produced from this frond. The New Zealand D. willana is 

 characterized, however, by lateral fronds proliferating from the 

 stout stipe. The attachment disc bears a resemblance to the primary 

 disc found in some members of the Laminariales, and it is formed 

 in much the same way by tangential divisions of the outer layer or 

 meristoderm. The growing region is the margin. Internally the 

 thallus possesses small hyphae which anastomose and fuse with 



195 



