DELESSERIA. 199 



ODONTHALIA. 



This is only found on the Northern coasts of England, 

 Yorkshire, and Scotland. It comes on shore from the deep 

 sea finely dotted with fruit in the month of November. The 

 beautiful stichidia, reddish purple, and the ceramidium both 

 kinds are on this plant. 



BONNEMAISONNIA, 



named after Bonnemaison, a celebrated French Algologist. 

 Nothing can be more graceful and beautiful than this ex- 

 quisite little plant ; the fronds so delicately ciliated, of a 

 bright rose colour, and dotted all along with tiny capsules 

 the true ceramidium ; each urn-like vase containing a group 

 of stalked spore-cases, in which are numerous seeds. The 

 texture of the plant also is a beautiful microscopic object. 

 It is found from June to September all round the English 

 and Scottish coast. 



DELESSERIA 



is only microscopic in its fructification, and as an example of 

 Sori. It has two kinds of fructification : 



1. Capsules, containing spores, and these are always 

 found upon the midrib and stem of the plant. 



2. Sori, or masses of granules collected into little spots 

 or lines in the substance of the frond, or in little leaflets or 

 distinct pod-like leafy processes, which form a sort of fringe 

 on the midrib and margin of the plant. We never find 

 more than one kind of fruit on any individual. 



Delesseria is a well-known and abundant Sea-weed, a 

 favorite in all collections, from its beautiful colour and 

 broad fronds. 



Delesseria limosa is found after storms attached to the 

 stems of Laminari digitata. Specimens have been gathered 

 in which the frond measured four inches across. 



There is one species, Delesseria ruscifolia, which deserves 

 microscopic attention from its substance between the midrib 

 and margin being transversed by white pellucid branched 

 composed of a single row of elongate cellules. The 



