THE MARINE ALG^E OF NEW ENGLAND. 151 



carps external, sessile or pedicellate, with a distinct carpostome, spores 

 in several masses composed of closely packed radiating filaments borne 

 on a basal placenta. 



A beautiful genus, comprising about twenty-five species, the most striking of which 

 are found in Australia, New Zealand, and at the Cape of Good Hope. P. coccineum is 

 very widely diffused in the North Atlantic and Pacific, and possibly also in tbe south- 

 ern hemisphere ; but it has only been observed once on the coast of New England, 

 and that perhaps requires verification. The genus is at once recognized by the branch- 

 ing. The frond is linear and distichously pinnated, the pinnules, which are always 

 alternately secund in groups of from two to five, being of two kinds ; the lowest 

 pinna is abort, simple, and acute, wbile tbe remaining pinnae are pinnulate or pecti- 

 nato-decompound. The cystocarps of Plocamium are similar to those of Bhodyrnenia, 

 and the zonate tetraspores are in special branchlets or leaflets, known as stichidia. 



P. COCCrNETJM, Lyngb.; Phyc. Brit., PL 44. 



Fronds narrowly linear, without a midrib, decompound pinnate, pinnae 

 alternately secund in threes or fours, the lowest subulate and entire, the 

 upper pectinate on the upper side; conceptacles marginal, solitary, ses- 

 sile ; tetraspores zonate on divaricately branching processes borne on 

 the inner side of the pectinated branchlets. 



Boston Bay, Miss SawTcsTiurst. 



The ahove-named locality, given in the Nereis, is the only one known on the New En- 

 gland coast, for this widely diffused species, if we except tbe vague statement of Bailey 

 in the American Journal of Science, Vol. Ill, 1847, p. 84, that it has been found by Rev 

 J. L. Russell on tbe coast of Massachusetts. One sometimes finds forms of Euthora 

 cristate labelled P. coccineum in American herbaria. The common Californian form of 

 the species is coarser than tbe European, and has been named by Kiitzing P. Calif or- 

 nicum. It is not, however, distinct. 



COBDYLECLADIA, J. Ag. 



(From KopdvXrj, a club, and Kladoc, a branch.) 



Fronds filiform, irregularly branched, carnoso-cartilaginous, formed 

 of two strata of cells; medullary layer of oblong, longitudinal cells, 

 cortical of roundish, colored, subseriated, vertical, minute cells ; con- 

 ceptacles sessile on the branches, subspherical, furnished with a cellular 

 pericarp at length perforate, containing a densely packed globular mass 

 of roundish-angular spores, formed by the evolution of much-branched 

 filaments issuing from a basal placenta ; tetraspores immersed in the 

 I>eriphery of pod-like ramuli, oblong, cruciately parted. 



? 0. Hunth, Harv. 



" Fronds densely tufted, springing from a common, expanded, crust- 

 like disk, livid purple, tereti-compressed, once or twice forked or se- 

 cundly branched; branches subulate, alternate, acute; fruit?" (Ner, 

 Am. Bor., Part II, p. 155.) 



Narragansett Bay, Mr, George Hunt. 



