41 



STRUCTURE OF THE GILL-rLATES OF AGARICS. 



By J. De Seynes. 



{Continued from Page 31.) 



Cystidium. — The cystidium is a coll generally larger tlian the 

 baeidium, and which varies much in its forms ; originating from 

 the parenchyma at the same level, or a little lower than the other 

 elements of the hvmenium, we see it raise itself straight and soli- 

 tary, sometimes as a simple sterile cell a little larger, sometimes in 

 a cone more or less long or slender, sometimes bearing at its ex- 

 tremity a little sphere (A. melinoides, A. sulcatus), sometimes 

 dividing itself, or again growing rotund, like a leathern bottle. 

 Tins organ does not exist amongst all the Uymenomycetes and the 

 Agarics, notwithstanding it has been indicated by Corda as being 

 the male organ, the antheridia, and he has given them the name of 

 pollenaire, which has been accepted by Mr. H. Hoffmann, although 

 this author refuses to attribute to them the same signification. It 

 appears to me, in fact, difficult to accept this interpretation. 

 Pretty numerous observations of these organs, some of them 

 undertaken without even knowing the hypothesis of Corda, led me 

 to an altogether different conclusion, and permit me to see, in the 

 cystidia, only organs returned to vegetative functions, by a sort of 

 hypertrophy of the basidium. Following Corda, fecundation is 

 effected by means of a viscous liquid issuing from these organs ; 

 but, if we remark that the examples of this kind of fecundation 

 are taken from mushrooms (A. rutilus, viscidus, jjiucosus), all the 

 vegetative portions of which are viscid, or have a tendency to 

 become so in damp weather, we shall see nothing surprising in the 

 cell belonging to them having the same property and agglutinating 

 like the spores ; there is nothing special in this ; we should be 

 tempted, on the contrary, to see in it an argument in favour of our 

 thesis, and to suppose from that that the cystidia are always allied 

 to the simple organs of vegetation. Amongst the milky Mycence 

 (A. galopus) which have besides organs of reproduction very dif- 

 ferent from those of the Lactaini, the cystidia shew themselves 

 identical with those of the Lactarii ; amongst the Plutei they take 

 the form of basidia to such an extent, that were it not for their 

 dimensions we should take them for true basidia ; divided into 

 short horns at the summit, they seem thus to have preserved the 

 sterigmata. The passing of one of these organs to the other has 

 been very well pointed out by M. H. Hoffmann, and figured in 

 particular in the Ag. albo-brunneus. (Bot. Zeit. 1856, p. 139.) At 

 other times the form of the cystidium approaches that of the cells of 

 the parenchyma; in a new Agaric, Agaricus sulcatus, I have 

 observed the cystidia forming little cylinders with swollen, spherical 

 extremities, and that is exactly the form which the vegetative cells 

 in the pilcus and the gills affect ; many have the form of simple 



