144 PEYSSONELIA. 



wedge-shaped leaves, varying in breadth from two to four lines, and in 

 length from one to three inches ; the segments somewhat truncate, often 

 proliferous from the apex, the young shoot rising with a cylindrical stem, 

 which soon expands into a frondlet resembling the primary one, and this, 

 in its turn, gives birth to a second or third. Nemathecia large, globose, 

 dark red, sessile on the tips of the frond, at length converted into monili- 

 form strings of tetraspores, (J. Ag.) 



4. Ph. Palmettoides, J. Ag. ; root a widely-expanded 

 disk ; stem cylindrical, filiform, simple or branched, expand- 

 ing into an oblong, narrow-obovate or cuneate, simple or but 

 once forked, rose-coloured frond, which is sometimes proli- 

 ferous ; sorus solitary, transverse, elliptical, near the apex of 

 the frond, immersed in its substance. Chotidrus Brodicei 

 fl. simplex, Grev. Alg. Brit, p. 133; Wyatt, Alg. Damn. 

 No. 121 ; Harv. Phyc. Brit. t. xx.^</. 2, 3, 4. 



On rocks, near low-water mark. Perennial. Winter and spring. Bare. 

 Coasts of Devonshire and Cornwall. Root a broad discoid expansion, an 

 inch or more across, from which a large number of stems issue. Stem fili- 

 form, half an inch to an inch high, simple or branched, terminating in a 

 rose-coloured, membranaceous, linear-obovate or cuneate, mostly simple 

 leaf, one or two inches long. This leaf is sometimes forked, and sometimes 

 bears small leaflets from its disk or apex. Towards the apex of the leaf, 

 in fertile specimens, is a large transverse, elliptical sorus, immersed in the 

 substance of the frond, composed of a multitude of minute tetraspores. 

 No other fructification has been observed. Nearly allied to the preceding, 

 but distinguished by the position of the sori, the brighter colour of the 

 frond, and form of the root. 



VI. PEYSSONELIA. Dne. [Plate 14, D.] 



Frond brownish red, depressed, rooting by the under-sur- 

 face, concentrically zoned, composed of several rows of cells, 

 disposed obliquely in filamentous, vertical series. Fructifi- 

 cation^ warts scattered over the upper surface of the frond, 

 formed of radiating filaments, and containing oblong, cru- 

 ciately-divided tetraspores. Name in honour of J. A. Peys- 

 sonel, an early and meritorious observer of marine plants. 



P. Dubyi, Crouan ; frond membranaceous, orbicular or 

 lobed, attached by the whole of the under surface. Harv. 

 Phyc. Brit. t. Ixxi. (colour much too pale.} 



Hob. On old shells, stones, &c. on scallop-banks, in 10 15 feet water. 

 Shores of the British Islands, not uncommon. Frond 1 2 inches across, 

 at first orbicular, afterwards irregularly lobed, membranaceous, thin, ad- 

 hering closely by its lower surface, which is clothed with short radicles, to 

 the surface on which it grows. Warts of fructification scattered, containing 

 a few large cruciate tetraspores, wilh very wide limbi. Colour dull brown- 

 red. The figure in Phyc. Brit, is badly coloured. 



