228 THE MYXOMYCETES 



structures described as spines or echinulations largely on one side. 

 These latter are easily detached, quite unlike the ordinary wall mark- 

 ings of a myxomycete spore, and seem to be rather of the nature of 

 plasmodic secretions. In this later collection there are a few short, but 

 unmistakable capillitial threads attached to the sporangium wall. 

 These are about 1 (x in diameter, with frequent plasmodic, not cal- 

 careous, thickenings. In spite of the very rudimentary capillitium, the 

 form is best regarded as a Licea, and quite distinct from any other 

 species. 



2. Hymenobolina Zukal 

 (Esterr. Bot. Zeitschr. 43 : 133. 1893. 



1893. Hymenobolus Zukal, (Esterr. Bot. Zeitschr. 43 : 73. 1893, non Dur. & 



Mont. 



Sporangia solitary, sessile, brownish gray, opening by a membranous 

 lid; wall single, limeless; capillitium none; spores smooth. Parasitic on 

 lichens, mosses and algae. 



Distinguished from Licea by the possession of a lid and the curious 

 parasitic habit of growth. According to the author it shows other differ- 

 ences in its development which substantiate the claim to generic 

 separation. The plasmodium does not move about but forms a nearly 

 stationary mass which gradually penetrates the substratum. In dry 

 weather it contracts to form characteristic reddish cysts. 



A single species : 



Hymenobolina parasitica Zukal 



(Esterr. Bot. Zeitschr. 43 : 133. 1893. 

 PL XVI, Figs. 397, 398. 



1893. Hymenobolus parasiticus Zukal, (Esterr. Bot. Zeitschr. 43 : 73. 

 1919. Licea singularis Jahn, Ber. Deutsch. Bot. Ges. 36 : 665. 



Sporangia scattered, sessile, subglobose or forming short plasmodio- 

 carps, 0.05-0.2 mm. in diameter, brownish gray, opaque or glossy, 

 dehiscing irregularly or by a well-defined lid, which may be either 

 smooth or areolate; sporangium wall membranous, pale purplish, 

 minutely papillose on the inner surface of the lid or throughout, the 

 lower part charged with refuse matter; spores subglobose, smoky 

 brown on one side, fading to pallid on the other, and surrounded by a 

 pale gelatinous sheath about 1 n thick; diameter, without the sheath, 

 11-16 ix. Plasmodium red. 



This curious species occurs rather commonly on the bark of various 



