446 



Goniotrichum Humphrey i, described in COLLINS, HOLDEN and 

 SETCIIELL, Phycotheca Bor.-Am., No. 421 and in COLLINS, The 

 Alga? of Jamaica (Proc. Amer. Acad., vol. 37, 1901, p. 251). 



4. Erythrotrichia carnea (Dillw.) J. Ag. 



5. Erythrocladia subintegra Rosenv. 



6. AcrochaBtium Sargassi Bergs. 



7. crassipes Bergs. 



8. pulchellum Bergs. 



9. netrocarpum Bergs. 



10. gracile Bergs. 



11. caBspitifornie nov. spec. 



Thallus parvus, gracillimus cgespitosus usque ad 700 fJ- altus 

 in Padina Howeana epiphyticus. Pars basalis e filis repentibus 

 plus minus lateraliter confluentibus composita. Cellulee sub- 

 breves, 8 iJ- longa? et 5 f* latse. 



Fila erecta quoquoversum ramosa, ad apicem versus atte- 

 nuata; ramis sparsis nonnumquam secundatis aut irregulariter 

 ortis. CeUulis in inferiori parte filorum ca. 5 p latis et 12 // longis, 

 in superiori ca. 2,5/* latis; in ramis paulo minoribus, inferioribus 

 3 4 fj. latis, superioribus ca. 2 /-/ latis. 



Kami recti, sub angulis acutis surgentes; in inferiori parte 

 eorum ramuli breves sporangia gerentes. 



Sporangia pedicellata aut raro sessilia, 11 12 // longa et 

 6 fjL lata. 



Chromatophorum parietale irregulariter lobatum aut per- 

 foratum pyrenoide laterali munitum. 



Upon a young Padina Howeana an Acrochastium was found 

 which I think must be regarded as a new species (Fig. 416). It 

 comes, undoubtedly, in several respects rather near to the Acr. 

 gracile described above on p. 26, but differs from this species in 

 its ramification and in the deviating arrangement of the spor- 

 angia. 



The plant forms small roundish tufts formed by the densely 

 placed and very ramified filaments. It grows with preference 

 along the edges of the Padina and the basal filaments run along 

 it. The base (Fig. 416 a), in which the original spore is not visible, 

 consists of filaments creeping upon the surface of the host. These 

 filaments merge more or less together, forming an often large, 



