(88) 



Descriptiox. — Root, a minute conical disc. Fronds filiform, single or 

 more or less tufted, three to ten or twelve inches long, and from a 

 quarter to half a line in diameter, much branched from near the base, 

 where it is slightly attenuated ; main branches dichotomous, nearly 

 cylindrical, erecto-patent ; ramuli short multifid, erect or very patent, 

 sometimes secund, irregularly dichotomous, forked at the extremities, 

 the apices incurved, occasionally straight, articulated throughout, and 

 constricted at the joints ; the articulations of the main branches about 

 twice those of the ramuli, about half as long as broad, entirely pervaded 

 by coloured cells. Substance membranaceous, rather flaccid, and gene- 

 rally adhering to paper. Colour, a fine deep transparent rather per- 

 manent red, changing in age to gi'eenish, and in decay to a more or 

 less yellowish green, or at length dull white. Favellro, formed by the 

 metamorphosis of one of the forks of the ramuli (T), roimdish, containing 

 numerous angular spores, inclosed in a thick limbus, and having at the 

 base two to four short articulated spine-like ramuli about the length of 

 the caps^^le ; not uncommon. Tetraspores wholly immersed, and arranged 

 circularly round the middle of the joints of the upper ramuli, tripartite, 

 generally abundant during the summer. 



The genus Ceramium is very closely related to Microdadia both in 

 structure and ft-uctification, but may be readily distinguished from it by 

 the absence of the lai-ge coloured cells, rendering the articulations of the 

 tube distinctly visible externally. 



The present fine species is one of the most widely distributed of the 

 Rhodosperms, if not of marine Algae, and generally occurs in great 

 abundance, growing on rocks, stones, old shells, and other Algse, and in 

 every situation, from high-water mark to a considerable distance beyond 

 the lowest "spring tides," and consequently presenting almost every 

 possible form of size, form, and colour — from the pale green, sickly- 

 looking scrubby dwarfs of the shallow tide-pool near high-water mark, 

 with only a few stiuited branches, to the fine luxiu*iant plants from deep 

 water, often upwai'ds of a foot in length, and of a fine deep pinky red 

 colom*. Frequently however the main stems and branches have more or 

 less of a greenish tint ; and when growing in shallow pools, much exposed 

 to the sun, they soon become of a yellowish or yellowish white. So 

 common is this species that in traversing the shore we scarcely find a 

 pool without its specimen, and not imfrequently we meet with low 

 lying shallow pools entirely filled with it ; and, unlike many of its more 

 fastidious neighbours, growing on rocks, stones, shells, and every species 

 of Algse within reach, even those species of less dimensions than itself 

 are not exempted from its parasitical attacks, as it is not unfrequently 

 found infesting Confervte and other filiform s^^ecies. 



