SYSTEMATIC ARRANGEMENT. 87 



formed is scarcely distinguishable from a spore, and we may 

 then have a passage from the ascigerous Fungi to the sporiferous. 

 It is thus that we have sometimes the two forms of fruit in the 

 same liymenium, as in Tympanis (Plate 1, fig. 13). 



I do not enter into the question of the affinities of Fungi 

 with other groups, because it supposes a knowledge of those 

 groups. 1 must refer, therefore, to what is said ujion the 

 subject in the ' Introduction to Cryptogamic Botany.^ 



As regards the affinities which exist between one group and 

 another, we must take care that species are not placed together 

 merely from similarity of external form. Nothing can be more 

 close, for instance, than the external resemblance between a 

 simple Clavaria and a Geoglossum (Plate 22, fig. 23), and yet 

 no Fungi are more essentially distinct. So long as the true 

 structure of the hymenium in the higher Fungi was unknown, 

 they might be associated, but to associate them now would be 

 to substitute analogy for affinity. Again, under similar cir- 

 cumstances,^ a Psilopezia and Corticium xm^\t be placed in the 

 same genus, but the asci of the former indicate its alliance with 

 Peziza, and not with AuricuJarini. On the contrary, the re- 

 lation of Hijsterangium to Phallus, though apparently so distant 

 when the latter is expanded, is most evident if the young plant 

 in the egg state be examined. And in the same way the rela- 

 tions of Tremellini to Uredines are clear, if the large, often 

 lobed or septate cells from which the long threads which bear 

 the spores are developed, be compared with the primary spores 

 of Podisoma, while it is remembered that these spores give 

 rise to little buds, whatever be their nature, from their sides, 

 which are at the very least analogous with the tertiary spores 

 of some UredinecB. The transition from Tremella to Tkele- 

 phora thi'ough such species as T. sebacea (Plate 17, fig. 6) is 

 almost perfect. 



