APPENDIX. 373 



* * * Frond plain, hyaline, composed of cells radiat- 

 ing from a centre. Fructification unknown. 



5. Lithocystis (a minute parasite). L. allmanni forms 

 minute white dots on Chrysimenia davelosa, consisting of 

 fanshaped fronds composed of square cells. 



4. DELESSERICE^. Frond cellular, continuous, areolated. 

 Coccidia external. Tctraspores collected into definite 

 clusters (sori). 



1. Delesseria.- Frond leafy, of definite form, with per- 

 current midrib. 



2. Nitophyllum. Frond leafy, of indefinite form. No 

 midrib (sometimes vague nerves). 



3. Plocamium. Frond linear or filiform, compressed. 

 Much branched, distichous, ramuli pectinate, secund. 



5. RHODYMENIACE^:. Frond cellular, continuous ; the 

 superficial cells minute. Coccidia external. Tetraspores 

 scattered through the frond or forming undefined, cloud- 

 like patches. 



* Frond flat, expanded, leaflike, dichotomous or pal- 

 mate. 



1. Stenogramme. Conceptacles linear, riblike. 



2. Hhodymenia. Conceptacles hemispherical, scattered. 



* * Frond compressed or terete, linear or filiform, much 

 branched. 



3. Sphcerococcus. Frond linear, compressed, two-edged, 

 distichously branched, with obscure midrib. 



4. Gracilaria. Frond filiform, compressed or flat, ir- 

 regularly branched ; the central cells very large. 



5. Jdypnea. Frond filiform, irregularly branched, 

 traversed by a fibro-cellular axis. 



6. CRYPTONEMIACE.E. Frond fibro-cellular, composed of 

 articulated fibres connected by gelatin. Favellidia im- 

 mersed in the frond or sub-external. Tetraspores immersed 

 in the frond. 



