(40) 



This pretty little species was at one time considered a variety of the 

 preceding, small specimens of which it closely resembles, the principal 

 difference consisting in the brighter colonr, smaller size, spare branch- 

 ing, but chiefly in the position of the tetraspores, the only kind of 

 fructification that has been observed. 



From that species also it differs in its geographical range of distribu- 

 tion, reaching its most northern limit in the sotith of England, whereas 

 P. Brodimi has only been found in the north of Scotland and Ireland. 



The species of this genus are all very closely related to each other, 

 both in form and structure, and still more so in the obsciu-ity in which 

 their fructification seems still to be involved. In no species has the fructi- 

 fication been fully investigated. In one species nothing but spores have 

 been observed : in another only tetraspores, and in another we hardly 

 know which, and yet most of the species are common — very common. 

 Sm-ely a careful search would supply more accurate information regarding 

 the fructification of these interesting plants. 



EXPLANATION OF PLATE LXXXL • 



Fig. 1. — Pliyllophora Palmettoides, natural size. 

 2. — Segment with tetraspores. 

 3.— TetrasiMrcs. 

 4. — Section of frond. All magnified. 



