DASYA ARBUSCULA. 201 



HALYMENIA 



has a compressed frond, pinky red, consisting of a very 

 delicate membrane, which when* in fruit is dotted with Sori, 

 and a transverse section should be made, which will show 

 the spores, called in this plant "favellidia" attached to 

 the inner surface of the membrane. It is found abundantly 

 on the coast on rocks and stones in the sea during 

 Summer. 



DASYA. 



There are four species of this lovely Sea-weed. The 

 name is taken from a Greek word signifying hairy. The 

 commonest of them, Dasya coccinea, is often mistaken for 

 Ptilota plumosa, being found, in long crimson feathery 

 sprays on the coast after storms, or dredged in deep water. 

 It is a great favorite with collectors of sea-weed for orna- 

 mental purposes, and is equally valuable for the microscope, 

 yielding two kinds of fructification; the Ceramidium, con- 

 taining pear-shaped spores, and the Stichidia, containing 

 tetraspores, ranged in transverse bands. 



A delicate section of the lower part of the stem will show 

 the internal structure, which is of numerous parallel tubes 

 surrounding a central cavity, and edged with a circle of the 

 short stout hairs which clothe the stem. 



Sections of the fruit and of the stem are often indispen- 

 sable for determining the species, and give innumerable 

 varieties of beautiful objects. 



DASYA ARBUSCULA. 



A delicate plant not uncommon at the verge of low- water- 

 mark in many parts of Scotland and in the Channel Islands ; 

 remarkable for its beautiful and abundant stichidia, clustered 

 amidst the fine ramuli, which cover the frond densely, and 

 are forked at the tip, jointed, and of a clear crimson-lake 

 colour, sometimes more or less brown, and always discharg- 

 ing its fine colour if left in fresh water. 



