100 BTNOPSI8 OF BRITISH SEAWEEDS. 



171. Bonnemaisoni 'son's Nitophyllum) \ frond 

 shortly stalked, fan-shaped or palmate, variously clefl into 

 numerous wedge-shaped segments, furnished near the base 

 with irregular, vanishing nerves ; Bpots of granules roundish, 



btered over the surface of the frond, Orev. Alg. Brit. p. SI. 



(Atlab, PL XL. Pig. 1S5.) 

 Delesseria Bonnemaisoni, Ag. Aglaiophyllum Bonnemaisoni, 



Endl. 

 Uab. Growing on the stems of Laminaria digitata, and on rocks 



and stones in 4-5 fathoms water. Annual. Summer. 

 The fan-like outline, scattered groups of tetraspores, and 

 obscure basal veins distinguish the present species from 

 other British Nitophylla. The nearest in affinity is cer- 

 tainly N. versicolor, from which the basal veins and the 

 proportionally smaller size of the cellules composing the 

 membrane, together with some small differences, more 

 easily seen than described, distinguish it. From N. Gme- 

 lini, which it resembles in form, it is at once distinguished 

 by the very different disposition of the tetraspores ; from 

 N. Hillice, by the thinner substance, smaller size, and less 

 minute spots of tetraspores ; and from N. punctatum, by 

 the different outline of the frond. Where the Nitophylla 

 luxuriate the shore is quite pink with them. 



172. Gmelini (Gmelin's Nitophyllum) ; frond short-stalked, 

 fan-shaped, with a roundish outline, variously cleft into 

 broadly wedge-shaped segments, waved, curled, rather rigid, 

 marked near the base (and sometimes over the surface) with 

 vague, vanishing nerves ; spots of tetraspores linear, con- 

 fined to the margin, Grev. Alcj. Brit. p. 82. (Atlas, PL 

 XXXVIII. Fig. 176.) 



Aglaiophyllum Gmelini, Mont. Delesseria Gmelini, Lamour. 

 Hab. South of England ; particularly large and abundant near 

 Plymouth. On rocks and the larger Alga?, near low-water 

 mark, and at greater depth. Annual. Summer. 

 From all the British species of Nitophyllum, except 

 N. laceratum, this handsome plant may be at once dis- 

 tinguished, when in tetrasporic fruit, by the marginal 

 position of the sori ; from N. laceratum it can only be 

 known by difference in form, in substance, and, in some 

 measure, by its brighter colour. When the plants are 

 freshly gathered, indeed, they are most easily separated, 

 N. Gmelini being known by a peculiarly crisp, rigid feel, 

 and N. laceratum by softness, and at the same time 

 toughness. The colour of the latter is more purple, and 



