224 



DR. SCHACHT, ON THE MICROSCOPE. 



mentioned Conifers opens, which takes place about the end of May or the 

 beginning of June, every perfect pollen-grain of Larix Europa^a, Abies 



Fig. 118. 



.4^ ' "' ''"., il^C^''^ 



Fig. 119. 



pectinata, Picea vulgaris, and Pinus sylvestris, exhibits the cellular body 

 mentioned by Meyer ; there may also be seen the fissure between the outer 

 and the inner membrane, i. e., between the pollen-cell and the cuticle ; 

 the latter seems to consist of two layers, on which account Meyer speaks of 

 three pollen-membranes. There is also to be seen above this fissure the small 

 pedicel-cell, and over this again a larger cell, which encloses a very mani- 

 fest large nucleus. Fig. 119 represents a ripe pollen- 

 grain of Larix Europaja seen in water ; (a) is the 

 terminal cell of the cellular body ; (?)) the larger 

 pedicel-cell ; (c) and (rZ) the smaller pedicel-cells, 

 having the appearance of fissures in the membrane 

 of the pollen-grain. In Larix the cellular body seems 

 frequently to be composed of four cells instead of 

 three. {See figs. 117 and 118.) The above-men- 

 tioned cellular body lies opposite to either side of 

 the arcuate space which is found between the two 

 lateral excrescences, and out of which at a later 

 period the pollen-tube emerges. At this place there 

 is to be found in the cuticle of Abies pectinata an 

 attenuated spot, which is rendered manifest in fa- 

 vourable positions of the pollen-grain bj^ the use of 

 sulphuric acid ; the same kind of spot probably exists in Picea vulgaris 

 and Pinus sylvestris, and it may be seen also in the cuticle of the Larch, 

 in which plant also the cellular body is situated opposite to this place of 

 egress of the pollen-tube. According to GeleznoiT, both the outer mem- 

 branes, and therefore the cuticle, are com- 

 pletely stripped off. Fig. 120 represents a 

 ripe pollen-grain of Larix Europaea imder 

 concentrated suljahuric acid. The contents 

 of it, as well as the true pollen-cell, have dis- 

 appeared ; some oily drops (;/) are to be seen 

 in the middle of the cuticle {ct\ which is un- 

 injured, but which has become rose-coloured, 

 and now exhibits two layers ; (;r) is the thin 

 spot in the cuticle intended for the egress of 

 the pollen-tube. The above-mentioned cel- 

 lular body may be seen most clearly and 

 beautifully in the pollen of the Larch, which 

 is round or nearljr so, and in which, as is well 

 known, the two lateral excrescences are wanting ; but nevertheless I have 

 derived more information from the study of "the pollen-grain of Abies 

 pectinata, Picea vulgaris, and Pinus sylvestris, for which it is necessary to 

 make use of acids and volatile oils. 



Fig. 120. 



