( ISO ) 



stem without veins, quite pellucid. Tetraspores roundish, sessile on 

 the upper edge of the pinnse, "sometimes containing eight grains, 

 each of which at maturity separates into four pieces (and becomes 

 a tetraspore 1) " (Phi/c. Brit.) ; and, on some individuals, the place of 

 tetraspores is supplied by clusters of hyaline cells, collected in dicho- 

 tomous threads, which are supposed to be antheridia. Substance rather 

 flaccid, and adhering to the paper. Coloiu-, a fine reddish pink, brownish 

 or yellowish at the base. Favelloe bilobed, sessile near the apices of the 

 plumules. 



This fine species seems to be not imfrequent on the south and south- 

 western shores of England, and may ultimately be found more generally 

 distributed than it has hitherto been considered, when its characters 

 and relations are better understood. 



From C. roseum it differs chiefly in the arrangement of the pinnules, 

 and in the veins with which the stems of these two species are more 

 or less pervaded, and from C. tripinnatum chiefly by the more entirely 

 pinnated plumules, and the solitary pinnules at the base of the pinnae. 



In our Plymouth specimens, the pinnse are often simple, long, and 

 slender, at other times one, two, or three pinnules are present, and some- 

 times these approach nearer to the base than what would be admitted 

 to be normally characteristic of the species. 



This species has been named in honour of W. Bon-er, Esq. of Henfield, 

 Sussex, to whom we are indebted for the discovery of this as well as of 

 many other valuable additions to British botany. 



EXPLANATION OF PLATE CXXVL 



Fig. l.—Callithamnion Borreri, natural size. 



2. — Plumule. 



3. — Pinna with tetraspores. 

 4. — Tetraspore from same. 

 6. — Plumule with favellffi. 

 6. — Portion of stem. 



7. — Portion of pinna with antheridia. All magnified. 



