THE MARINE ALO.E OF NEW ENGLAND. If^O 



Fronds parenchymatous below, Imt above formed of loosely uniti'd 



lilanients, tetraspores formed in \\w liliunents PffroccUs, 



52. Fronds tnbnlar 5;^ 



Fronds fdamentous ."i I 



Fronds inend)ranaeeons . . 7.") 



5o. Fronds eartilay:inous, hollow thron^hout, ri^id, proliferous, tetra- 

 spores cruciate Ilahsaccion. 



Fronds slender, nnieh contracted at the Joints, but without dia- 

 phragms, tetraspores tripartite in depressed cnx'ities .. Lojnentar id. 

 Fronds slender, nodose, with diaphragms at the nodes, tetraspores 



tripartite in the cortical layer Champia. 



o t. Fronds monosiphonous, without proper cortex 55 



Fronds with distinct axial and cortical layers Gii 



bo. Fronds monosiphonous throujihout: 5G 



Fronds at tirst nu)nosiphonous, becoming polysiphonous above, 

 spores formed by divisions of any of the cells, filaments simjde, 



gelatinous, dark purple Tiduf/ia. 



Fronds monosiphonous above, but below with a false cortex formed 



by descending filaments given off from the cells GO 



Fronds formed of large cells placed end to end, with bands of smaller 

 cells at the nodes, in some cases the nodal cells extending in a 



thin layer over the internodal cells 01 



5G. Spores (as f\ir as known) formed directly from the contents of any 



of the cells 57 



Spores on short pedicels, distinct, undivided Trentepohlia (?). 



Tetraspores and eystocarps present b>^ 



57. Filaments simple, forming a tine web over other algne. 



Erythrotrichia. 



Filaments dichotomously branching, minutely tufted. . Gonioirichum. 



T)S. Fronds formed of prostrate filaments, from which arise erect i>innate 



filaments, eystocarps terminal, involucrate, spores irregularly 



grouped, not surrounded by a common 'gelatinous envelope when 



mature Spermathamnion. 



Cystocaq)S terminal or lateral, spores irregularly grouped at ma- 

 turity, covered by a general gelatinous envelope 59 



59. Fronds dichotomous, formed of delicate vesicular cells, tetraspores 



in whorls at the Joints, involucrate Griffitlmia. 



Fronds dichotomous or pinnate, tetraspores scattered on the 

 branches, solitary or aggregated, eystocarps lateral, usually bi- 

 nate Callitliamnion^ in i)art. 



Fronds with a monosiphonous axis, nearly concealed by the densely 

 whorled bnmches, cystocaq)s terminal on short branches, tetra- 

 spores in wh<>rls one above another on special branches. .7/^^ /?//•?/.•?. 



60. Fronds capillary or bushy, densely branching, cortications confined 



to the larger branches, and evidently formed of vein-like descend- 

 ing fdaments CulUthamnion, in jKirt. 



