1925] Setch ell-Gardner: Melanophyceae 545 



J. G. Agardh (1882, p. 40) took up Cladosiphon from the point of 

 view of Meneghini's Liehmannia Posidoniae, a species seemingly at 

 present, at least, to belong to another genus (MeneghinieUa) from the 

 tj'pe of Kuetzing. 



Derbes and Solier founded the genus Castagnea on a species they 

 named C. polycarpa, presumably from the neighborhood of Marseilles, 

 but the locality is not mentioned. This species has the gametangia 

 produced as outgrowths from the convex sides of the upper cells of 

 the curved cortical filaments and this peculiarity is made a part of 

 the diagnosis of the genus. Derbes and Solier state that their genus 

 Castagnea is readily distinguishable from the related genera Lieh- 

 mannia, Stilophora, and Nereia by the form of the filaments associated 

 with the organs of fructification in that they are cylindrical and not 

 terminated by large swollen cells. Castagnea polycarpa Derbes and 

 Solier has been variously and usually doubtfully referred by later 

 writers and we have found no reference to the existence of an authentic 

 specimen. Derbes and Solier compare its appearance to that of a 

 stunted Liehmannia. In their later ( ?) paper, Derbes and Solier 

 (Sur les organes repr. des algues, 1850, p. 269, pi. 33, figs. 12, 13) 

 seem inclined to consider their C. polycarpa closely related to, if not 

 identical with, the "Cladosiphon. fistulosum" of Kuetzing, a binomial 

 unknown to us, but presumably the Mesogloia fistulosa Zanard. (in 

 Meneghini, 1843, p. 292) and considered by Kuetzing (1849, p. 547) 

 to be a synonym of his Cladosiphon mediterraneus. There is certainly 

 suspicion here that Castagnea and Cladosiphon may have been founded 

 on the same type species. In the absence of that exact proof which is 

 difficult to obtain other than from type specimens and experience 

 from type localities, we feel justified in considering these two genera 

 as identical in foundation. We may call attention to the fact that 

 Bornet (1892, p. 236) has placed the Cladosiphon mediterraneus 

 Kuetzing under Castagnea. 



The genus Eudesme was founded by J. G. Agardh (1882, p. 29) 

 on the Mesogloia virescens Carmichael, i.e., at least technically. There 

 is good reason to believe that Agardh did not restrict his ideas to type, 

 but had a composite idea as to the nature of his E. virescens. He 

 speaks of an "axis solidescens" whereas Eudesme has been applied as 

 typically including species whose axial filaments are readily separable 

 from one another (cf. Kjellman, 1893, pp. 225, 226) and as they are, 

 to a certain extent at least, in what may be considered to be typical 

 E. virescetis, viz., Alg. Danm., no. 49 ; but even here there is a definite 



