70 BRITISH CHAIiOPHY'J'A. 



(ii) eruptive, granularly decorated, wine-red 



N. spanioclema. 

 (iii) smooth, tubercularly decoi-ated, chestnut 



brown ..... JV. captllaris. 

 (2) Membrane thin and flexible — 

 (i) reticularly decorated. 



(a;) meshes measuring c. 15-18 /x 



Nt translucens. 



(b) meshes measuring c. 9-10 fi 



N. mucronata. 



(c) meshes measuring c. 4-5 (U 



JV. tenuissima. 

 (ii) granularly decorated. 



(a) granular density 8-10 per 10// 



N. batrachosperma. 



(b) granular density 6-8 per 10 /u N.hyalina. 



(c) granular density 5-7 per 10 /t N. gracilis. 



II. Oospore terete, ovoidal, spheroidal, or ellipsoidal. 

 Membrane translucent or semi-opaque ; smooth or decor- 

 ated; thin or thick; flexible or semi rigid . . Tolypella. 



(1) Membrane granularly decorated — 



(i) membrane thin and flexible, granules very 



small and faint . . . . T. intricata. 

 (ii) membrane tiiick, granules conspicuous 



T. glomercda. 



(2) Membrane sruooth — 



(i) membrane yellow, thin and flexible 



T. prolifera. 

 (ii) membrane wine-red, thick and semi-rigid 



T. nidijica. 



III. Oospore large terete, broadly obovoidal. Mem- 

 brane thin, flexible, translucent, dull-yellow-brown, 

 finely and obscurely granulate. Granular density c. 15 



per 10 ju . . . . . . NiTELLOPSIS OBTUSA. 



IV. Oospore terete, long, narrowly ellipsoidal. Mem- 

 brane thick and brittle, opaque, very dark red-brown, 

 finely and obscurely granulate. Gri-anular density c. 5 

 per 10 /i . . . . Lampeothamnium papdloshm. 



