24 h'KSKAHClIKS ().\ FrXGI 



would lie entirely wasted. Not a single basidiospore would lie shot 

 uj) tar enough to succeed in escapins^ from a Peziza cup; wliilst in 

 a Mushrooiu or I'olyporns the ascospores, when discharged, would 

 strike and adhere to tlu; opposite hyinenial surfaces. An upwardly- 

 looking, Peziza-like, cup-shaped Hymenoinycete, provided with 

 typical basidia and liberating its spores into the air, is just as 

 impossible as a Mushroom- or Polyporus-shaped Ascomycete with 

 its hymeniuni composed of typical explosive asci. Where, in the 

 Hymenomj^cetes, as in the genus Cyphella, the fruit-body has the 

 forni of a saucer, a cup, or a filter funnel, with the hymeniuni 

 inside, its mouth looks not upwards but downwards, so that ii 

 resetnbles an inverted Peziza. It is true that the conical Aviue- 

 glass-shaped fruit-bodies of the species of the hymenomycetous 

 genus Craterellus stand erect. Here, however, in contradistinction 

 to Cy])hella, the hynieniuin is borne on the exterior of the fruit - 

 bodies, whilst the interior is barren. The position of the basidia of 

 a Craterellus is exactly the reverse of that of the asci in the 

 erect wine-glass-shaped fruit-bodies of certain Ascomycetes. These 

 remarks may serve to emphasise the close correlation betw'een the 

 mechanism for spore-liberation and fruit-body structure. 



The Effect of Sunlight upon Spores. — Some years ago, Massee ^ 

 expressed the view that the hymeniuni of the Hymenomycetes, 

 during progressive phylogenetic development, had come to be 

 placed on the lower sides of the pilei, instead of t>n the upper, 

 for the purpose of concealing it from the light. On the other 

 hand, my own researches seem to show that the position ot the 

 hymeniuni has been primarily decided by the necessity of the 

 basidia being so placed that they can readily liberate their spores 

 into the air. Other, but subsidiary, advantages accruing to the 

 hymenium from its position on the lower side of a pileus, rather 

 tlian the upper, are: protectiou from lain, falling leaves, i\;c., and 

 undue transpiration in dry weather. 



The exact ett'ect of direct sunlijlit npdii the spuns ot Hymeno- 

 mycetes still remains to be worked out. In the ('lavar;e;e. many 

 species live in fields. \c., where their hymenial surfa(;es are freely 



 <;. Massee, "A M<iuu;^ra'j,li of J5.iti.sli Ciastnniiycutus,'' Ami. uf Hot., vol. iv. 

 1889, p. ^. 



