CARPOSPOREM. 385 



all possible intermediate stages exist between two extreme forms, the simplest being 

 that form in which the sporocarp produces only a single spore or a single mother- 

 cell in which spores are formed, the most complex being that in which the sporocarp 

 exists as an independent plant and produces countless spores. 



The sporocarp is derived from a female organ which we will term the Carpo- 

 gonium. It is only in the simplest case that the carpogonium is a single cell, and 

 then it sometimes resembles very closely the oogonium of Class III, especially 

 when, as in the Coleochseteae, fertilisation is effected by means of motile anthero- 

 zoids, or when the unicellular carpogonium is fertilised by a tube growing from the 

 male organ {Sordaria, Podosphcerd), just as is the case in the Saprolegniese. In the 

 majority of Cases, however, the carpogonium is multicellular before fertilisation, and 

 its cells contribute in different ways to its further development; some absorb the 

 fertilising substance, whilst others give rise to that part of the fructification which 

 produces the spores. This division of labour is very evident in the Ceramieae and 

 other Florideae, as also in many Ascomycetes (e. g. Ascobolus furfuraceus). It 

 occurs both in unicellular and in multicellular carpogonia that a more or less 

 elongated tubular projection arises from the carpogonium, the function of which is 

 the absorption of the fertilising substance. This organ, which takes no part in the 

 subsequent development of the fruit, is termed the Trtchogyne, a name given by 

 Thuret and Bornet to this organ in the Floridese. Like the style on the ovary 

 of Phanerogams, the trichogyne of the Carposporeae may be sometimes well- 

 developed, and sometimes entirely absent. For instance, in Characeae and in many 

 Ascomycetes {Sordaria, Erysiphe) it is wanting ; it is only imperfectly developed in 

 Peziza confluens, and it is well- developed in Coleochaeteae and Florideae. The male 

 reproductive organ occurs in very various forms in the different groups of Carpo- 

 sporeae, this variety being evidently dependent upon the varying form of the carpo- 

 gonium and the habitat of the plant. In Coleochaeteae and Characeae only is 

 fertilisation effected by motile antherozoids ; in Florideae it is effected by cells which 

 are conveyed passively, and in most Fungi by tubular outgrowths. 



Should it be suggested as an argument against the existence of a relationship 

 between the true Fungi and the green plants which are included within this class, 

 that the difference of habit between them is very great, it might be replied that the 

 tissue of many Fungi presents striking resemblances to that of many Florideae. The 

 hyphal tissue of many gelatinous Fungi finds its analogue in the gelatinous tissue of 

 many Florideae. The rows of cells too, of which the mycelial filaments (hyphae) 

 of Fungi consist, differ only in habit from the branched rows of cells of which the 

 thallus of many Coleochaeteae and of very many Florideae consists. 



It must be remembered that, in order to detect the relationships existing 

 between different groups of plants, the simplest and not the highest forms are those 

 which must be compared. If this be done in this case, it becomes evident that the 

 simplest Florideae are connected on the one hand with the Coleochaeteae and 

 Characeae, on the other with the simplest Ascomycetes. Each of these series of 

 forms, however, becomes developed into higher forms in some particular direction, 

 and so if the most perfect Ascomycetes be compared with the most highly-developed 

 Florideae and Coleochseteae, only a very slight similarity between them will be 

 detected. 



