THE ALGAE OF BERMUDA. 139 



in transferring to the latter the other species of Schmitz's Plumaria, 

 a new specific name is needed for Ptilota elegans, and we have taken 

 Harvey's name as the next in order. 



G. bipinnatum sp. nov. ; filamentis basalibus circa 20-25 /j, diam., 

 ramificatione opposita, cellulis diam. 4-5, raro 6-7 longis, membrana 

 crassa, nodis subconstrictis; axibus erectis basi 20-25 n diam. superne 

 attenuatis, ad apicem circa 12 n, cellulis cylindricis vel subclavatis, 

 inferioribus circa 3 diam. longis, apicem prope 1-1| diam.; ramis 

 oppositis apice cellulae singulae exeuntibus, parallelis, angula 50°-60°, 

 rectis vel leviter recurvatis, axi referentibus sed minoribus, raro 15 /i 

 diam. superantibus; ramorum aliis simplicibus, aliis et pluribus ramu- 

 los secundatos latere superiore ferentibus; ramulis 1-2-cellularibus, 

 perraro magis; circumscriptione frondis ovata vel lanceolata; cellulis 

 terminalibus rotundatis. Filamentis prostratis ramulos rhizoideos 

 descendentes ferentibus, axibus erectis oppositis, cellula terminali ad 

 substratum disco affixa. Tetrasporangiis in ramis et ramulis termi- 

 naUbus, sphaericis vel subovoideis, 30-35 ij, diam., tripartitis. Plate 

 IV, fig. 26. 



Basal filaments about 20-25 /i diam., with opposite branching, 

 cells 4-5 diam. long, rarely 6-7, wall thick, nodes somewhat con- 

 stricted; erect axes of about the same size near the base as the pros- 

 trate filaments, diminishing to 12 ij, at apex; cells about 3 diam. long 

 at base, near apex 1-1| diam., cylindrical or slightly clavate, each 

 bearing at the upper end a pair of opposite branches, forming an 

 angle of 50-60° with the axis, straight or slightly recurved, similar 

 to the axis, but averaging smaller, seldom over 15 ^ diam.; these 

 branches either simple or more commonly bearing on the upper side, 

 on part or all of the cells, a second series of branches, 1-2 cells long, 

 rarely more, 8-10 ju diam.; outline of frond ovate or lanceolate; 

 terminal cells all rounded. Basal filaments producing, opposite to 

 the erect axes, rhizoids of one or many cells, the end cell forming a 

 disk of attachment when it reaches the substratum. The end of a 

 basal filament sometimes becoming erect and developing into a frond 

 similar to the erect axes; the erect axis sometimes extending beyond 

 the pinnation, and after an indefinite number of unbranched cells, 

 developing a second series of branches; or the prolonged naked axis 

 descending and forming a prostrate filament bearing erect axes and 

 rhizoids. Tetrasporangia terminal on the branches of the first and 

 second orders, spherical or slightly ovoid, 30-35 ^u diam., tripartite. 

 Cystocarps? Antheridia? On wall of cave. Gravelly Bay, April, 

 Hervey, type in Collins herbarium; on Wurdemannia, Harrington 



