BONNEMAISONIA LAURENCIA. 97 



III. CHRYSYMENIA. Frond hollow, filled with watery mu- 

 cus, neither constricted nor chambered. [Plate 13, A.] 



TV. CHYLOCLADIA. Branches hollow, filled with watery 

 mucus, constricted at intervals, and chambered. [Plate 

 13, B.] 



I. BONNEMAISONIA. Ag. [Plate 12, D.] 



Frond filiform, inarticulate, compressed or plane, solid, 

 much branched, the branches margined with distichous, awl- 

 shaped, alternate cilia. Fructification : ceramidia, contain- 

 ing a tuft of pear-shaped spores. Tetra&pores unknown. 

 Name, in honour of M. Bonnemaison, a French naturalist. 



1. B. asparagoides, Woodw. ; frond compressed or sub- 

 terete ; ceramidia stalked, opposite the cilia. Grev. Alg. 

 Brit. p. 106, t. 13 ; Hook. Br. Fl. ii. p. 295 ; Harv. Phyc. 

 Brit. t. li. Fucus asparagoides, E. Bot. t. 571. ft. teres ; 

 frond capillary, terete, cilia very long. 



On rocks near low-water mark, and at a greater depth. Annual. Sum- 

 mer. |3. at Wicklow, and in Kingstown Harbour, Dublin. Frond 4 12 

 inches long, compressed or nearly cylindrical, varying in breadth from a 

 capillary fineness to nearly a line, excessively branched ; branches disti- 

 chous, alternate, simple, or bearing a second series, gradually shorter up- 

 wards, set throughout at short distances with subulate, distichous ramuli, 

 I or 2 lines long and extremely slender. Capsules ovate, with a short stalk, 

 placed opposite to the cilia, containing a tuft of pear-shaped spores. Fre- 

 quently the capsules are abortive, and then a minute process occupies their 

 place. In a specimen communicated by Mrs. Wyatt, the place of capsules 

 is occupied by a tuft of ramuli, which do not, however, produce telraspores, 

 but occasionally one of them, thicker than the rest, bears a capsule. Colour, 

 a fine transparent crimson, darker in those from the west of Ireland, and 

 in them becoming darker in drying, while in those from the east of Ireland 

 and south of England the colour fades considerably in drying. Substance 

 soft and flaccid. 



II. LAURENCIA. Lamour. [Plate 12, C.] 



Frond cylindrical or compressed, linear, pinnately branched, 

 the apices obtuse ; structure cellular, solid. Fructification 

 of two kinds, on distinct individuals; 1, ceramidia, contain- 

 ing a tuft of pear-shaped spores ; 2, triparted tetraspores, 

 imbedded in the ramuli. Name, in honour of M. de la Lau- 

 rencie, a French naturalist. 



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