RHODOMELACE^I. 109 



large branches, hidden by a thick layer of irregular cells ; 

 those of the branchlets visible, the lower ones four times, 

 the upper twice as long as broad. Spores in egg-shaped, 

 stalked conceptacles ; tetraspores roundish, in swollen 

 branchlets. 



This elegant plant is a native of many parts of our 

 coast. It grows on rocks, stones, or sea-weeds, near 

 low-water mark, attains perfection in the months of 

 May and June, and is annual. It varies a good deal 

 in size, and in the greater or less development of the 

 branchlets, which in some specimens are very luxuriant. 

 It is of a soft, silky texture, and adheres closely to 

 paper. 



Polysiphonia fibrillosa. The fibrillose Poly- 

 siphonia. 



Fronds growing singly or in tufts, from four to ten 

 inches long, of a pale-brown colour ; stem thick, running 

 distinctly through the frond, not at all, or only once or 

 twice divided ; branches alternate, spreading, thick; branch- 

 lets numerous, very slender, always tipped with jointed, 

 forked fibres ; articulations of the stem and branches, more 

 or less hidden by narrow wavy cells ; those of the lesser 

 branches and branchlets visible, rather longer than broad. 

 Spores in egg-shaped, stalkless conceptacles ; tetraspores 

 large, in the terminal branchlets. 



This plant is annual, and common in most places 

 during the summer. It grows in sunny pools between 

 the tide- marks. In some respects it resembles P. vio- 

 lacea, but has shorter, less tufted branchlets and shorter 

 articulations, and is of a paler colour than that species. 

 It is also more constantly fibrillose. 



