244 M. Miiller on the Development of the Lycopodiacese. 



ever, I can oppose no further reasons to them, since this observer 

 has not unfolded his ideas sufficiently in detail. Meantime the 

 figure of the antheridium of L. annotinum which he gives in the 

 second edition of his work is represented in such an advanced 

 state, that it cannot by any means be regarded as a proof of the 

 origin of the antheridium from the leaf. Since the leaf and the 

 antheridium are formed simultaneously, it is naturally the ear- 

 liest stage alone which can yield evidence in the history of the 

 formation of the two organs. 



But by this history of the mode of formation, moreover, the 

 independence of the family of Lycopodia is shown most indubi- 

 tably, and the gap which formerly existed between them and the 

 Ferns is again established (compare Roper in the ' Flora Mek- 

 lenburgs.,' 1 Th., 1843, p. 127). More of this however here- 

 after. 



b. The formation of the spores. That which is now perfected 

 in the interior of the antheridium is the so-called spore. The 

 essential points relating to its form have already been given in 

 the commencement of these observations on the development of 

 the antheridia. I pass therefore to the history of their develop- 

 ment. 



According to H. von Mohl the spores are formed here exactly 

 in the same manner as pollen-grains, and this has already been 

 pointed out above in that observer's own words. From my own 

 researches I can of course confirm that here also the spores are 

 formed in mother-cells ; meanwhile I have not attained to a com- 

 plete history of the development in L, denticulatuin, because in 

 fact I neglected it. The reason however was this : I wished to 

 give a perfect history of the formation in a Lycopodiaceous plant 

 with very large spores; thus to make certain at once, in what 

 peculiar manner the contents of the mother-cells become divided 

 into four parts — whether this, as some observers hold, occurs 

 through division by means of septa, or whether, as others will 

 have it, it is effected through the agency of cytoblasts. To this 

 end I traced the formation of the spores in Psilotum triquetrum, 

 which I obtained in a living state through the kindness of Prof. 

 Kunze of Leipzic. In the first place, however, two words on the 

 internal structure of the antheridium of L. denticulatum. If once 

 successful, after many long preparations, in obtaining a very fine 

 longitudinal section of the antheridium in a very young condition, 

 we notice a threefold layer in its internal cavity (PI. V. fig. 11). 

 First the outermost or true epidermis : this is composed of a 

 layer of parenchyma of some density which passes off to the fruit- 

 stalk. To this follows a second layer of empty, transparent and 

 delicate parenchymatous cells : this is continuous with the elon- 

 gated cells in the fruit-stalk. Then comes the third layer which 



