PERICHjBNA.] ARCYRIACEjE. 201 



thickly encrusted -with numerous round, angular, or rod-shaped 

 bodies, only very partially consisting of lime, the upper part 

 marked on the inside with delicate bands forming a regular 

 reticulation with 5 to 6 angled meshes, 12 /a diam. Oapillitium 

 scarcely evident, consisting ■ of few weak, simple, or branched 

 yellowish threads 1'5 to 2 jn diam., unequally warted. Spores 

 golden-yellow, delicately warted, 12 to 14 ;«, diam. 



Hob. On beech bark. — Denmark. 



This description applies perfectly to forms of P. populina with 

 scanty oapillitium. 



9. P. nitens Eaunk., I.e., p. 55. Sporangia solitary or 

 clustered, globose-pyriform, sessile or shortly stipitate, dehiscing 

 irregularly, greyish-brown with a violet metalhc lustre, 0'5 mm. 

 diam. • wall single, almost without deposits of granules. Oapilli- 

 tium of long weak threads, slightly branched, attached to the 

 sporangium-wall by irregular enlargements, unequally and 

 deHcately spinulose, of equal breadth throughout, 1 to r5 /x. 

 diam. Spores delicately spinulose, yellowish, 10 to 12 f/. diam. 



This description suggests a small-spored form of P. populina. 



10. P. Knipii Eacib., in Hedw., xxviii., p. 124 (1889). 

 Sporangia chestnut-brown, rarely globose, depressed, solitary, 

 usually flat creeping plasmodiocarps, irregularly ring-shaped or 

 vermiform, 0'5 to 1"2 mm. long, plasmodiocarps as much as 

 15 mm. in length, 0'5 to 0-75 mm. high; sporangium-wall simple, 

 iridescent, chestnut-brown, finely warted, breaking away as a 

 lid in the upper part. Oapillitium forming a dense web of rather 

 thick-walled threads, 0-3 to 1'5 /i diam., covered with crowded 

 irregularly shaped, wart-like ' thickenings giving a toothed 

 appearance, without constrictions, rarely branching; oapillitium 

 connected with the sporangium-wall by many thin smooth 

 connecting threads. Besides these there are small, short or 

 long outgrowths from the sporangium-wall 2 to 12 /u. long, 1 to 

 3 IX thick, 200 to 500 on a square millimetre of the wall. 

 Spores globose, brownish -yellow, minutely warted, 7 to 8'5 j«,diam. 



Hab. On bark.— Tatra Mounts, Poland. 



This description suggests a species of Dianema, possibly D. eorticatum. 



11. P. ? pseudsecidium Speg., in Ann. Soc. Cient. Argent., 

 xxii., p. 187 (1886). Sporangia cylindrical, conical, or calyciform, 

 1 to 1-5 mm. long, 0*5 to 1 mm. broad, sessile or shortly stipitate, 

 wall very thin cartilagino-membranaceous, base even or minutely 

 rugulose, dehiscing at the apex in an irregularly laoiniate or 

 fimbriate manner, chestnut or brownish; mass of spores and 

 capilHtium citron or yellowish ; oapillitium threads very slender, 

 1 fi, thick, sparingly branched here and there with solitary 

 conical or elongated branch-like spines, yellowish ; hyaline. Spores 



