400 Meyen's 'Report for 1839 on Physiological Botany. 



form of cells of extraordinary smallness, as in the anthers of 

 the Mosses. 



M. Unger draws the following results from his observa- 

 tions : — 



1st. That the original development in Riccia glauca of both 

 those organs is simultaneous, and that they therefore seem 

 to have a nearer relation to each other. 2nd. That both 

 organs represent cavities formed from cellular tissue, which 

 are provided with lengthened openings, and that therefore a 

 ma^ericZ communication of their contents is not improbable. 

 3rd. That the function of the neck-shaped passage of the 

 sporangium is confined to the earliest period of its develop- 

 ment, etc., and that, finally, the transference of the contents 

 of the anthers to the sporangia is a cause of the formation 

 of spores. 



M. Mohl has published some new and very fruitful obser- 

 vations on the development of the spores of the Jungerman- 

 nia : he chose for his experiments Anthoceros kevis, in 

 which the primitive spore contains but few globules, which 

 renders the progress of the formation easier to follow. The 

 youngest primitive cells which M. Mohl found appeared as 

 transparent, partly spherical cells, in which one could observe 

 a cell-nucleus, as in the phanerogamic plants. Afterwards a 

 gummy substance was formed round the disc of the nucleus, 

 and this finally covers more than half of it ; the green 

 granules appear more plainly, and the mass divides into two 

 parts. At the edges this green mass passes into a colourless, 

 gummy, but fine granular substance, which forms larger or 

 smaller meshes ; M. Mohl compares this substance very 

 correctly to the bladders of foam. After this divided green 

 mass has gradually increased, these two halves divide again 

 into two parts, and thus four nuclei, lying close to each 

 other, are formed (grain-cells, M. Mohl calls them), in which 

 change the true cell-nucleus takes no part, but lies separated 

 by itself. At the same time the side of the primitive cells 

 thickens, and adopts the form of the Mell-known mucous 

 substance, and now follows the division of its cavity. Lines 

 are formed on the inner surface of the primitive cell, which 

 are correctly represented as projecting edges, which after- 

 wards grow towards the middle of the cell between two 

 masses of granules, and join together. After this division, 

 nothing is visible of the nucleus. A short time after the 

 division of the primitive cell, the formation of the spore-cuti- 

 cle commences, namely, in each of the four compartments, 

 and the granular masses lie in the interior of each of these 

 new-formed cells, and are fastened by threads of gum to the 



