130 COLUXS AND HEEVET. 



Dasta Agardh. 



1. Divisions few, subsimple, ramelli very dense at tips. 1. D. ocellata. 



1. More branched; ramelli less dense at tips. 2. 



2. Ramelli all unbranohed or forkings narrow. 3. 



2. Ramelli divaricately or squarrosely branched, at least near base. 5. 



3. RameUi deciduous, leaving short, acute, spinous branches. 



3. D. spinuligera. 



3. RameUi more persistent; no spinous branches. 4. 



4. Ramelli very slender, short-celled, generally distributed on all but the 



oldest parts. 2. D. pedicellata. 



4. Ramelli larger, longer-celled, in more or less distinct whorls. 



4. D. punicea. 



5. Ramelli stout near their base, diminishing at each forking, very slender 



at apex. 6. 



5. Ramelli nearly uniform in size throughout. 5. D. arbuscula. 



6. RameUi forming a very dense coating, especiaUy near tips of branches. 



6. D. ramosissima. 

 6. Ramelli in minute, subcorymbose clusters, not denser near apices. 



7. D. corymbifera. 



1. D. OCELLATA (Grat.) Harvey in Hooker, 1833, p. 335; 1846-51, 

 PL XL; Ceramium ocellatum Grateloup, 1807, p. 34. Cooper's 

 Island, Feb., Farlow; on Sargassum, Gibbet Island, Jan., Gravelly 

 Bay, Feb., Hervey; tetraspores in Jan. 



2. D. PEDICELLATA Agardh, 1824, p. 211; D. elegans Harvey, 

 1853, p. 60; Kiitzing, 1864, p. 21, PI. LIX. Kemp, as D. pediculata; 

 Merriman; Miss Peniston; Miss Wilkinson; Shelly Bay, April, 

 Collins; Buildings Bay, March, Hervey. The common Dasya of the 

 Atlantic coast from Cape Cod to Florida, but evidently not common 

 here. Though the name D. elegans has been long familiar, it will 

 have to be given up for D. pedicellata, the priority of which is unques- 

 tionable. 



3. D. spinuligera sp. nov.; P. B.-A., No. 2188. Cellulis peri- 

 centralibus 5, corticatis, cortice glabro, continue, cellularum minonun, 

 elongatarum; ramis paucis, elongatis, ramulos breves, paten tes, 

 acutos, gerentibus; apice ramuli junioris fasciculum densiun ramel- 

 lorum ferente, adultioris nudo; rameUis densissimis, deciduis, mono- 

 siphoniis, dichotomis, rectis nee divaricatis, cellulis 2-3 diam. longis, 

 supeme 1 diam. modo, diametro ubique aequaU; stichidiis conicis 

 vel cyUndro-conicis, prope basin fasciculi rameUorum ortis; tetra- 

 sporangiis 2-^ in verticillo; frondis substantia lirma; colore rubro 

 obscuro. Plate IV, figs. 24-25. 



Pericentral cells 5, corticate, cortex smooth, even, of small elongate 



