f)74 Howe : Phycological studies 



The only specimen from the American side of the Atlantic 

 which has heretofore been referred to the genus Dudresnaya is, so 

 far as we know, one collected in the Tortugas, Florida, by Mrs. 

 G. A. Hall and described as new by J. Agardh in 1899 under the 

 name " Dudresnaja canescens" (Anal. Alg. Cont. 5: 88). This, 

 however, is a plant of entirely different habit from ours and is not 

 a Dudresnaya, as a recent examination of the single type-specimen 

 in lib. Agardh has shown. 



The auxiliary-cell branches and cystocarps are very abundant 

 in our material and we have been able to observe nearly all stages 

 in their development and mutual relations, though without any 

 serious attempt to study the internal cytological changes. In 

 their general features, the fusion of the sporogenous filament and 

 the auxiliary-cell and the subsequent development of the cystocarp 

 take place very much as described and figured for D. coccinea by 

 Bornet and Thuret and by Oltmanns. However, Thuret's de- 

 scription (/. c.\ gives the impression that the fusion can take place 

 with any one of three similarly enlarged cells of the auxiliary 

 branch, while in D. crassa it seems always to occur with a single 

 definite highly specialized cell lying between the two larger ones. 

 The content of this cell appears at first very much like that of the 

 adjacent cells, but as it matures it undergoes a change, becoming 

 more homogeneous and translucent ; at the same time the auxili- 

 ary-cell and the two neighboring cells become enveloped in an 

 especially thick layer of mucus which stains yellowish with saf- 

 ranin. We regret that the behavior of the carpogonial branch 

 after fertilization has escaped observation in this species. Carpo- 

 gonia occur in moderate number in our material (we have seen 25 

 or 30), but all seemed unfertilized ; and the sporogenous filaments 

 travel such long distances that we have failed in attempts to trace 

 them back to their ultimate source. 



The type-specimen — no. 313 — is associated with a CJian- 

 transia, which permeates it, more or less, and fringes its surface. ] 



C. MISCELLANEOUS NOTES 

 Caulerpa ckassifolia (Ag.) J. Ag. Till Alg. Syst. 1 : 



13. 1872 



Caulerpa taxifolia fi crassifolia Ag. Sp. Alg. I : 436. 1822. (Ex 

 eluding synonymy.) 





