brefeldia] 



HETEEODEEMACEAE. 



173 



Hob. On dead wood, etc. — Lyme Regis, (B.M. 2699) : Darenth, 

 Kent (B.M. 1110) ; Wanstead, Essex (B.M. 2700) ; Luton, Beds (B.M. 

 1418a); Birmingham (B.M. 1418); Boynton, Yorks (B.M. 1159); 

 France (Paris Herb.); Sweden (K. 781); Germany (B.M. 2249); 

 Switzerland (Hb. Zurich) ; Mass., U.S.A. (B.M. 1419) ; Iowa (B.M. 

 1020). 



Cohort ll.—LAMPROSPORALES. 



Spores variously coloured, not violet-brown or purplish -grey, 

 except in Licea minima and Listerella, q.v. 



Subcohort l.—ANEMINEAE. 



Capillitium absent or not forming a system of uniform 

 threads, except in Alwisia, q.v. 



Order I. — Heterodermaceae. 



Sporangium-wall membranous, studded with microscopic 

 round granules (plasmodic granules), either continuous or 

 forming a net in the upper part ; capillitium wanting ; spores 

 4 to 7 /j. diam. 

 KEY TO THE GENERA OF HETERODERMACEAE. 



Sporangia sessile, compacted or aethalioid, the wall not form- 

 ing a net in the upper part. (26) Lestdbladia. 



Fig. 34. — Lindbladia effusa Rost. 



a. Aethalium. Xatural size, 

 ft. Vertical section of aethalium. 



Magnified 6 times. 



Fig. 34. 



Sporangia stalked ; sporangium-wall with thickenings in the 

 form of a delicate persistent net expanded at the nodes. 



(27) Cribraria. 



Fig. 35. — Cribraria aurantiaca Schrad. 



a. Group of sporangia. Twice natural size. 



b. Sporangium after dispersion of the spores. 



nifled 20 times. 



Mag- 



Fig. :J5. 



Sporangia stalked ; sporangium-wall with thickenings in the 

 form of nearly parallel ribs extending from the base to the 

 apex, connected by delicate threads. (28) Dictydium. 



