262 ENDOSPOREAE [HYMENOBOLUS 



purplish-brown, clothed externally with dark granular refuse- 

 matter except along the margins of the four to six lobes of 

 dehiscence. Capillitium scanty, consisting of slender flexuose 

 pale purplish-brown threads, 0*5 /x diam., marked at intervals 

 of 1 to 2 /* with bead-like thickenings, attached below and 

 perhaps above also to the sporangium-wall. Spores in mass 

 blackish-brown ; when magnified faintly spinulose, 7 to 8 /x 

 diam., pale brownish-grey with a paler patch of dehiscence on 

 one side. 



PI. 191. — d. e. sporangia ; /. capillitium and spores with fragment of sporangium- 

 wall : (North Germany). 



This minute and inconspicuous species has been found scattered 

 over the stems of " reindeer moss " (Cladonia rangiferina) by Herr O. 

 Jaap near both Hamburg and Triglitz in Xorth Germany, and by Herr 

 G. Lindau near Berlin. In size and external appearance Listerel/n 

 paradoxa resembles Licea minima, but as Dr. Jahn points out, the presence 

 of the capillitium completely separates the genus from the Liceaceae ; 

 he suggests that it should be the type of a new family, the Lister •eUacear. 

 It is placed here provisionally among the Margaritaceae, but its true 

 position is at present uncertain. It may perhaps be allied to Dianema, 

 but is distinguished by the regular moniliform markings of the 

 capillitium, and by the dusky colour of the spores. 



Hob. On stems of Cladonia. Triglitz, Holstein (B.M. 3183). 



A DOUBTFUL MYCETOZOON. 



Hymenobolus Zukal in Oester. Bot. Zeitschr., xliii. 73 

 (1893). Sporangia solitary, sessile, brownish-grey. Sporan- 

 gium-wall single, without lime. Capillitium very scanty? or 

 none. Spores globose, having the spore-wall thinner on one 

 side. Plasmodium parasitic on lichens and algae. 



H. parasiticus Zukal I.e. Plasmodium rosy-red. Sporangia 

 scattered, sessile, subglobose, or hemispherical and depressed, 

 often irregular in outline, 0.05 to 0.2 mm. diam. brownish-grey, 

 opaque or glossy, dehiscing irregularly or by a well-defined 

 lid ; sporangium-wall membranous, pale-purplish, minutely 

 papillose on the inner surface, usually invested with a thick 

 layer of refuse-matter in the lower part. Capillitium possibly 

 of scanty hyalines paringly- branched threads, 05 /x diam., 

 arising from the sporangium-wall ? or entirely absent. Spores 

 smooth, brown, subglobose, 13 to 16 tt diam., the spore- 

 wall paler and thimier on one side ; the contents of the spore 

 consist in part of rosy granules. 



This minute species is fully described by Zukal, who succeeded 

 in cultivating the plasmodia on fragments of willow-bark. Although 

 closely allied to the true Mycetozoa it differs from them in the two 

 following characters : the amoeboid swarm-cells do not pass through a 



