250 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



from beginning to end. Before, however, I pass on to this 

 I propose to make a few preliminary remarks concerning the 

 ■distribution of the spores themselves and the actual genesis 

 of the fern plant, drawing attention to the two very distinct 

 generations alternately produced, viz. the minute ovary-bearing 

 generation, or prothallus, and the relatively large spore-bearing 

 generation, constituting the ferns as popularly known. 



The diagrams exhibited show the varied forms of fructifi- 

 cation on the common polypods in the shape of rounded heaps, on 

 the hart's-tongue as long sausage-shaped masses, and on the 

 lastreas as small patches covered with the characteristic kidney- 

 shaped cover. The components of these heaps are next shown 

 largely magnified, viz. the sporangia, or spore capsules, then 

 the spores themselves, followed by the various stages of formation 

 of the primary leaf, or prothallus, constituting the first generation, 

 and the organs subsequently formed on the under side of this, 

 which by sexual interaction eventually produce the fern as we 

 know it, or secondary generation. 



It is one of the remarkable facts connected with ferns that 

 the microscopic size of the spore and the minute herring-scale 

 size of the prothallus it produces are common to all ferns, so 

 that even the huge, wide-spreading tree ferns, such as the Cya- 

 theas, Dicksonias, and others, are produced from spores which 

 are invisible to the naked eye, and by the fertilisation of what 

 are practically flowers, which are also so small that only prac- 

 tised vision can detect their existence. 



Ferns, however, amply compensate for the diminutive size 

 of the spores by their enormous numbers. I recently took a fine 

 specimen of Athyrium filix f amino, in my collection, a very 

 fertile variety of the common lady fern, and by counting the 

 fronds and their divisions, secondary and tertiary, and multiplying 

 these by the number of spore heaps on each of the minor divi- 

 sions, these heaps again by the average number of capsules to a 

 heap, and finally these by the number of contained spores, I 

 arrived at the immense total of eleven hundred and twenty 

 millions. 



[The lecturer then exhibited a series of six slides, showing 

 the splendid set of drawings by which Count Suminski illustrated 

 his discovery, which completed the normal life cycle of the fern 

 & I above described.] Few original discoveries find such a 



