lycogala] lycogalaceae 201 



cushion-like mass of closely convoluted sporangia ; these are at first 

 separated by delicate sporangium-walls, and narrow tubular air- 

 passages communicating with the exterior are left between them. 

 Sections of such an aethalium show that the sporangia in the deeper 

 parts measure from 40 to 50 /x diam., while at the periphery they are 

 continued into larger lobes having a diameter of 100 li. At a later stage 

 the outer convolutions become superficially subdivided, flattened and 

 folded on themselves. The formation of this peripheral layer of larger 

 lobes marks the first differentiation of the cortex of the aethalium. 

 As maturation proceeds the limiting layer which at first invested the 

 young sporangia disappears except in the interstices where it forms 

 the membranous walls of the air-spaces and constitutes the pseudo- 

 capillitium. At maturity the cortex is formed of two layers, an outer 

 and an inner. The former bears on its surface thick- walled, isolated 

 vesicles, 20 to 200 ll diam., containing nucleated deeply-staining 

 protoplasm ; the nuclei remain sharply defined till after the spores are 

 formed in the aethalium, when they degenerate and disappear. Except 

 for the contents of these vesicles, both layers of the cortex are free 

 from nuclei. The protoplasm is withdrawn into the deeper parts of 

 the aethalium from the wide peripheral lobes, and the tubular air- 

 spaces between them fall together to form the matted layer recognizable 

 at maturity in the hyaline outer wall of the cortex. The inner layer 

 of the cortex consists of a finely granular membrane of varying thickness 

 penetrated by air passages extending from the outer layer and becoming 

 continuous with the pseudo-capillitium. The division of nuclei by karyo- 

 kinesis prior to spore formation has been observed in the young 

 aethalium of this species, and the resulting spores are found at maturity 

 to be separated by tubular air-passages without any trace of true 

 capillitium. In L. flavo-fuscum the membrane of the pseudo-capillitium 

 is more delicate than in L. epidendrum, and is in some parts perforated 

 with irregular lattice-work openings. The presence of spores in the 

 tubes, which is occasionally found in L. flavo-fuscum, may be explained 

 by the penetration of sporeplasm through such openings. 



KEY TO THE SPECIES OF LYCOGALA. 



Cortex of aethalia smooth or areolated. 1. L. flavo-fuscum 



Cortex of aethalia warted — 



Aethalia subglobose. 2. L. epidendrum 



Aethalia conical. 3. L. conicum 



1. L. flavo-fuscum Rost. Versuch, 3 (1873). Plas- 

 modium white or pale pink. Aethalia usually solitary, 

 rounded, sessile, or subpyriform and shortly stalked, 2 to 

 5 cm. diam., ochraceous-brown or purplish-brown, smooth, 

 minutely areolated ; cortex thick, of three layers, the outer 

 membranous, the middle consisting of a dense aggregation 

 of yellow vesicles, 50 to 80 \x diam., intermixed with the 

 peripheral ends of the pseudo-capillitial tubes, the inner 

 layer homogeneous, pierced by these tubes. Pseudo- 

 capillitium consisting of irregularly branching and anasto- 

 mosing nearly colourless smooth or somewhat wrinkled 

 papillose tubes, 6 to 20 ll diam., with numerous wide expansions 

 at the axils and free rounded ends. Spores in mass pale buff, 



