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STRUCTURE OF THE GILL-PLATES OF AGARICS. 

 By J. De Seynes.* 



Arriving at the gills, the cellular fibres, which have contributed 

 to the formation of the parenchyma of the other parts, take a 

 rectilinear direction, being inflected only outwardly towards the 

 walls, in order to bear the hymenium. They fork and anastomose 

 less than in the pileus ; still, in A. ceraceus for example, we can see 

 the anastomosed sub-hymenial cells fork frequently, almost remind- 

 ing us by their delicacy and their general aspect of the mucilaginous 

 tissues of Exidia. This system of cells is not the only one in this 

 Agaric, and stronger cells, filled with a clear yellow liquid, which 

 colours the parenchyma, sustain this delicate trellis-work. Most 

 frequently we see the organs which constitute the hymenium in- 

 serted directly upon the fibriform cells more or less inflected in 

 order to sustain them to their extremities ; at other times, one, two, 

 three, or four spherical or polygonal cells intervene. As for the 

 hymenium, properly so-called, its study offers numerous points of 

 interest ; as for that of the mycelium, it is necessary, in order to 

 find a precise and accurate description, to go back to a memoir of 

 Mons. Leveille, read at the Philomathic Society, on the 12th of 

 March, 1837, and inserted in the " Annales des Sciences Naturelles." 

 The same name is given to the spore-bearing organs of the 

 Agarics and to those of the Pezizas ; certain plates, such as those of 

 the memoir of Dutrochet upon A. crispus, show sufficiently how 

 necessary it was that an earnest study of them should be made. The 

 report to the Philomathic Society upon the memoir of M. Leveille 

 gives a just idea of its importance. 



The hymenium is not a membrane stretched upon the hymen o- 

 phore ; nothing can be better isolated than its cellular elements, 

 which are simply side by side, and in contiguity. It results from 

 this idea, well understood, that, as the organs of reproduction are 

 those which individualise the living being, an Agaric may be re- 

 garded as an agglomeration of cellular fibres, varying according to 

 the place through which they pass, and terminating in fructifying 

 organs. Such was also the conclusion which Dutrochet deduced 

 from his observations upon A. crispus. 



Three cellular organs compose the hymenium of the exosporous 

 Ilymenomycetes. The basidium or formative and nutritive organ, 

 analogue of the thecal amongst the Discomycetes ; a cell sometimes 

 smaller than the basidium, sometimes of equal dimensions, which 

 appears to me the analogue of the paraphyses ; in fine, a cell which 

 varies much in its form and dimensions, named cystidium by M. 

 Leveille, and of whose functions the celebrated mycologist was 

 unaware, but which he compares to the paraphyses, whilst the 

 other cells are named by him proper cells of the hymenium. These 



* Translated from his " Flore Mycologique." 



