vib of tlic sporopliyll, homisplievical, tliick-wallcd, containing a nearly glo- 

 bular tuft of moniliform sporcthrcads. The sori arc in pairs, one at each 

 side of the midrib of the sporopliyll. The colour, when fresh, is a rather 

 dull pale-red, becoming paler on exposure, and brownish in the herbarium. 

 The substance is very rigid and tough, and the frond in drying does not ad- 

 here to paper. 



Under Delesseria coriifolia (Plate CL.) I remarked that the 

 structure of its membrane was different from that of most others 

 of the genus Delesseria, except B. TlooJieri,^ and that these two 

 species formed a natural section or group, which might be con- 

 sidered as a separate g'enus. I now find a similar structure in 

 the frond of I), ivibricata, Aresch. ; and, taking into considera- 

 tion the difference of substance, as well as of cellular structure 

 between these three species of the Southern Ocean and all other 

 Delesserice, I think they constitute a well-marked and natural 

 generic group, which I propose to call Chauvinia, in memory 

 of a distinguished French botanist who made the Algse his 

 special and most beloved study. The genus Chauvinia, Bory, 

 founded on a part of the older genus Caulerjja^ has not been 

 generally adopted by botanists. The group to which I now 

 give M. Chauvin's honoured name is, I trust, established on 

 characters universally recognized by systematic botanists as suf- 

 ficient in defining genera among Algse. The structure must be 

 regarded as a step in advance over that of Delesseria. It is 

 very like that of Stenogramme or of RJwdj/menia. 



Chauvinia Hookeri (Del. Hookeri, Fl. Nov. Zeal. t. cxiv., cxv.) 

 is one of the very noblest of southern Rhodosperras, its brilliant 

 fronds being sometimes nearly two feet long and several inches 

 wide. C. imhricata, here figured, is both of common occurrence 

 and small size, but when well coloured and free from parasites, 

 is a very pretty little plant. C. coriifolia, which is intermediate 

 in size, is perhaps the rarest of the three. • 



Fig. 1. Chauvinia imbricata, — the natural size. 2. A sporophjU or fruit- 

 leaf, bearing a conceptacle. 3. Section of a conceptaele and part of the 

 sporophyll, showing the cellular structure of the membrane. 4. Spore- 

 threads from the conceptacle. 5. A sporophyll, with a sorus of tetraspores. 

 6. Tetraspores, from the same : — more or less Idglily magnified. 



* 2). Middendorfii was also doubtfully alluded to, but a microscopic examina- 

 tion of its frond shows it to be a true Delesseria. 



