V. CRYPTONEMIACE^. 187 



a beautiful rosy red or purplish lake. Substance delicately membranaceous. It 

 closely adheres to paper in drying. 



Dr. Dui-kee's specimen, noticed above, is irregularly branched, the primary stems 

 fihform and straggling; the secondary either pinnated or furnished at one side only 

 with pinnules. I have seen British specimens similar to this in ramification. 



XVI. CHRYSYMENIA, /. Ag. ref. 



Frond subterete, compressed, or flat, tubular or solid, branched ; the tube some- 

 times nearly empty or with a few percurrent longitudinal filaments, sometimes 

 filled with interlaced filaments ; peripheric stratum composed internally of large, 

 roundish-angular, inflated cells, externally of minute, coloured, vertically seriated 

 cellules. Conceptades half immersed in the frond, hemispherical or with a promi- 

 nent orifice, containing a simple nucleus (favella) fixed to a basal placenta, sur- 

 rounded by anastomosing filaments, and consisting of very numerous, densely- 

 packed minute spores enclosed within a membrane. Tetraspores cruciate, scattered 

 among the superficial cells of the frond. 



This genus, as at present constituted, includes plants of very difierent habit, and 

 in some respects of difterent structure. In the genuine species (sections Halichrysis 

 and Chrysymmia, J. Ag.) the frond is dichotomous or pinnated, evidently tubular, 

 but having the tube sometimes compressed, sometimes inflated, nearly empty, or 

 traversed by a very few slender filaments, which are often obsolete in the full- 

 grown plant. In our section Crypiamchne, the frond, which is either flat or cylm- 

 drical, is more or less densely filled with anastomosing, branched, often closely in- 

 terwoven filaments, but the external habit of the species is not very dissimilar to 

 that of the former sections. Finally, in the section Botryocladia, J. Ag. a much 

 branched, filiform, solid stem bears inflated ramuli, having the proper structure of 

 the genus. The species of this section depart widely in external habit from the 

 rest ; and yet they are perhaps nearer in affinity to the typical species than are 

 those of our section Cryptarachne. 



Sect. 1. Chrtstmenia {Halichrysis and Chrysymenia, J. Ag.) ; frond compressed or 

 inflated, evidently tubular; the tube empty or nearly so. 



1. Chrystmenia Enteromorpha ; frond saccate, fusiform, somewhat compressed, 

 delicately membranaceous, proliferously-decompound ; secondary fronds and their 



bb2 



