8TRUCTURE OF THE GILL-PLATES OF ACJARICS. 29 



latter, generally considered as simple terminations of the cells of 

 the parenchyma, called by Hoffman sterile cells, and by Corda 

 basilary cells, have always, for this Latter author, the same morpho- 

 logical signification as the paraphyses. Whilst giving them this 

 name of basilarv spores, which would seem to indicate a situation 

 inferior to that of the other organs, Corda lias very well shown in 

 his fine plates the real position which they occupy; one might even 

 reproach him with having done it in a more regular and geometrical 

 manner than occurs in nature. We readily establish this situation 

 on the same plan, at the same height as the hasidia. The structure 

 is the same as that oi* the fertile basidia, there are cases even in 

 which they are all transformed into fertile basidia (" Icon. Fung.," 

 p. 1<>, heft. ii.). There are also Pezizas, amongst which we may 

 show that, at an advanced period of their development, the number 

 of thecse is greater than that of the paraphyses, and in excess of 

 the proportions which those two organs habitually bear towards 

 each other. In the Agarics, among which the hymenium is neither 

 too fertile nor too barren, the basidia are intermixed with the 

 sterile cells, like the thecae in the midst of the paraphyses. 

 Amongst the Discomycetes, the paraphyses become lengthened in 

 such a manner that they seem to lose their analogy with the thecae ; 

 nevertheless, intermediate stages may be observed, and I have 

 remarked in Pe:i:a eximia a cell, which had commenced by having 

 the dimensions of a young thecae, arrested in its development, and 

 take the attenuated form of a true paraphysis. The paraphyses 

 appear sometimes to "specialise" in their functions, by charging 

 themselves with the colouring principle which gives the hymenium 

 its proper colour ; but if the theca3 are transparent, it is because 

 they have employed in the fabrication of the spores these same 

 colouring matters, which can be discovered, although very diluted, 

 amongst the latter; P. aurantia furnishes us with an example. 

 Thus the paraphyses of the Discomycetes have their analogues in 

 the cellules proper, and the sterile cellules of the hymenium, 

 although they are frequently shorter than the fructifying organ, 

 which is not the case with the paraphyses ; but this question of 

 size does not appear to us a sufficient reason for neglecting this 

 analogy. "In the hymenium of the Discomycetes" says the cele- 

 brated mycologist of Prague, " the form of the envelope is the 

 primary direction of life, and. therefore it is that paraphyses and 

 the thecaj are on the same level ; in the hymenium of the basidia- 

 bearing mushrooms, the increase is directed towards the exterior, 

 and therefore the basidium is raised as well as the pollenaire 

 above the mother cells, which replace the paraphyses. and form the 

 surface of the hymenium.* 



* This consideration, expressed in a somewhat abstract manner, merits further 

 development. If we understand it properly, it iimounts t this: among the 

 Asconvycetes, one might say a centripetal force retains the spore, and renders it 

 the centre to which everything converges. In effict, the theca envelope's the 

 spore ; the paraphyses are raided, and have a tendency to envelope the theca which 



