EE VISED LIST OP MARINE ALGLE. 139 



stem solid, ramuli tapering at both extremities 



Naccaria 



81. Axis composed of loosely woven, elongated verti- 



cal filaments, peripheral filaments composed of 

 large pear-shaped cells. Fronds undivided, 

 beset with numerous simple or slightly branched 



tapering branches Helminthocladia 



Axis composed of oblong cells, surrounded by 

 slender, long-jointed filaments, from which the 

 dichotomously radiating peripheral filaments 

 arise. Fronds very much and irregularly 

 branched Helminthora 



82. Branches much contracted at the base Chondria 



Branches not contracted at base ... 83 



Fronds red-brown, hollow below, branches 



tapering to both extremities, spores arranged 



in irregular masses ... ... Glceosijphonia 



83. Fronds rose-red, stems slender, ramuli simple, 



subulate, acute, apices not involute, cystocarps 

 stalked alternate with the ramuli Bonnemaisonia 



Fronds dark-red, much branched, rather robust, 

 superficial cells small, polygonal, irregularly 

 placed, apices of branches not involute, tetras- 

 pores in the young branches or palmately 

 divided receptacles (stichidia) Bhodomela 



Fronds purple or brownish purple, superficial 

 cells quadrate, apices of the branches strongly 

 involute, tetraspores in swollen pod-like 

 branches (stichidia) Bostrychia 



Fronds purple or red, occasionally blackish, 

 articulated either throughout or at least in 

 the young branches, the articulations longi- 

 tudinally striate 81 



