GENERAL SUMMARY 461 



fact that the fungi in this group are parasitic on shrubs and produce 

 their hymenial layers high above the ground on the surface of living 

 leaves, etc. 



In the Hydneae, the increase in the surface-area of the hymenium 

 beneath the pileus has been effected by the development of positively 

 geotropic spinous processes (teeth), instead of by gills as in the 

 Agaricineae, or by hymenial tubes as in the Polyporeae. Each spore 

 is discharged from its sterigma only after the emission of a drop of 

 fluid from the hilum, as in other Hymenomycetes. 



The gelatinous consistence of the fruit-bodies of the Tremellineae 

 is correlated with the lignicolous habit of the group. When sticks 

 bearing Tremellineae dry up, the fruit-bodies dry up too but retain 

 their vitality. When rain comes again, the water is rapidly absorbed, 

 not by capillarity as in Lenzites and other non-gelatinous lignicolous 

 fruit-bodies, but by imbibition. After absorbing water and expanding, 

 a gelatinous fruit-body immediately resumes its work of producing and 

 liberating spores. 



The period between the first appearance of a spore on its sterigma 

 as a tiny rudiment and its discharge with drop-excretion is very short 

 in the Tremellineae : 1 hour 20 minutes in Calocera cornea ; 1 hour 

 15 minutes in Exidia albida and 50 minutes in Dacryomyces deliquescens. 

 This rapidity of spore- development is correlated with the fact that the 

 spore-walls are thin and smooth, and with the fact that the fungi are 

 lignicolous. 



The author discusses the problem of septation in the basidia of the 

 Tremellineae and attempts to solve it from the physiological point of 

 view. 



The spores of the Tremellineae are more violently discharged than 

 those of the non-tremelloid Hymenomycetes, but somewhat less violently 

 than those of the Uredineae. In violence of spore-discharge the 

 Tremellineae thus take up an intermediate position between the 

 Hymenomycetes in general and the Uredineae. In those Tremellineae 

 in which the hymenial surface often looks more or less upwards, great 

 violence of spore-discharge is distinctly advantageous from the point 

 of view of the dissemination of the spores by the wind. 



The author redescribes the basidial and oidial fruit-bodies of 

 Dacryomyces deliquescens and points out that, hitherto, they have been 

 regarded by certain systematists as belonging to different species. 



In the Clavarieae, the hymenium is exposed on the surface of the 

 fruit-bodies. Some simple fruit-bodies, e.g. those of Clavaria pistillaris, 

 are obconic in form, so that the hymenium looks more or less down- 

 wards. In compound Clavariae the successive branches are usually 

 more or less obconic in form , so that here again the hymenium tends to 

 be so placed that it looks horizontally more or less downwards, thus 

 favouring the dispersal of the spores. In most Clavariae the basal 



