156 INTRODUCTION TO THE STUDY OF FUNGI 



cells of this layer have great capacity for swelling. Inwards 

 from the collenchyma is a white layer, the innermost region 

 of which is the inner peridium, while the outer, which may 

 be called the split layer, consists of soft, loosely-woven hyphae, 

 which pass at many points into the inner peridium. When 

 the fungus is quite matured, the outer peridium, through the 

 influence of moisture and the swelling of the collenchyma 

 layer, bursts outwards from the apex in a stellate manner, 

 forming several lobes, which turn back, so that the upper 

 surface, which is covered by the collenchyma, becomes convex. 

 The split layer is by this means so torn to pieces that its 

 constituent parts remain hanging as perishable flakes, some to 

 the collenchyma, some to the inner peridium. It is known 

 that the collenchyma layer retains its hygroscopic qualities a 

 long time, and the outer peridium -remains a long time lying 

 on the soil, stellate in shape, spreading out its rays in moist 

 weather, and bending them inwards when dry. The flaky 

 investment of the outer peridium is often more strongly 

 developed in G. fimlriatus and G fornicatus, and in the latter 

 it is composed of the finest of hyphae ; it tears away from the 

 fibrillose layer when the peridium is ruptured, and lies on the 

 ground, beneath the peridium, as an open empty sac. The 

 extremities of the lobes remain for the time firmly united 

 to the margin of this sac, and as the collenchyma layer 

 expands greatly, the star formed by it and the fibrillose layer, 

 especially in G. fornicatus, becomes convex upwards, and 

 carries the inner peridium on the apex of the convexity." * 



The genus Colostoma, when carefully examined, shows many 

 points of affinity with Geaster. Massee has given full details 

 of its morphology, 2 which should be perused in extenso, but the 

 following is a summary. On the authority of Hitchcock it is 

 stated that in Colostoma cinnabarinum the Fungus on bursting 

 from the soil is enclosed in a gelatinous envelope, like 

 Ithyphallus invpudicus, nearly a quarter of an inch in thickness. 

 This immediately bursts, even, before the whole body of the 

 Fungus has risen above the ground, and the exterior part of it 



1 De Bary, Fungi, etc. , English edition, p. 316. 



2 Massee, "Monograph of the Genus Calostoma," in Aimals of Botany, 

 vol. ii. p. 25, 1888. 



