No. 13.] [July, 1873. 



(SntrtlUa, 



A MONTHLY RECORD OF CRYPTOGAMIC BOTANY 

 AND ITS LITERATURE. 



NEW BRITISH ALG^E. 

 By E M. Holmes. 



Callithamnion hormocarpum. JV. S. — General characters : Frond 

 capillary, densely tufted, 1-2 inches high, of a pinkish purple colour. 

 Stems not glossy ; as thick as bristle below, becoming as fine as 

 silk above. Plumules alternately branched throughout. 



Microscopical characters : Articulations at the base of the stem, 

 coated with branched and jointed filaments ; articulation of the 

 plumules, 6-8 times as long as broad ; those of the pinnae four 

 times, decreasing to twice as long as broad ; flexuose and attenuated 

 towards the apex of the ultimate pinnules. Pinnules of the pinnae 

 either simple, once forked, or repeatedly forked, and tufted at the 

 apex ; axils very narrow, so that the less-branched pinnules appear 

 pinnate, and the more densely branched ones appear furcate. 



Fructification of two kinds : 1st, Tufts of branched moniliform 

 cells, of a darker colour than the cells of the frond, each cell sur- 

 rounded by a hyaline border ; these tufts are situated on the rachis 

 of the plumules and pinnae, but are never formed from the terminal 

 branchlets. 2nd, Elliptical cells, two or three in number, forming 

 a whorl round and semi-immersed in, the upper part of the articu- 

 lations of the plumules. 



Both the tufts and the whorls of cells appear to contain granular 

 matter, but show no appearance of being tetraspores. 



This very remarkable plant bears some resemblance to Seriospora 

 Grijjithsiana, but differs from it in its want of gloss, different colour, 

 in the moniliform cells never being terminal, and not formed from 

 the branchlets, but an independent growth on the rachis, and in the 

 presence of the whorled elliptical cells. It is interesting to find 

 that there is a specimen in Mrs. Griffith's collection of Alga} be- 

 longing to the Linnean Society, which was gathered at Salcombe, 

 in 1840, and which presents the same character of tufted cells, eve. 

 This specimen is marked " Seirospora ?" 



I have gathered the plant at Plymouth for two consecutive years, 

 and it has always presented the same characteristics. It grows on 

 Fuci at low water, on the Torpoint mudbank, and is thrown up on 



