FERNS. 



313 



into an error in certain important respects ; for example, 

 tie has represented what is undoubtedly an archegoniuni 

 filled with cellules, sperm-cells, which, he states, " emerged 

 from it as from the antlieridiar This description is not 

 quite correct. 



The reproduction of ferns had, until within the last few 

 years, been a vexed question among botanists. The riddle 

 w^as at length solved by the labours of Count Sumiuski, 

 who discovered that it is in the structures developed from 

 the spores in germination that the pistillidia and antheridia 

 of ferns are to be sought. The nature of the phenomena 

 by which the propagation of ferns is effected, is as follows. 

 In all the different species of ferns, the spores are contained 

 in brown dots, on lines collected on the under surfaces, or 

 along the edges of the fronds. Each of the spore-cases 

 is surrounded by an elastic 

 ring, which when the time 

 arrives for the spores to be 

 set free, makes an effort 

 to straighten itself, and in 

 so doing causes the spore- 

 case to which it is attached 

 to split open, and the spore 

 dust to be dispersed. Very 

 soon after these spores 

 have begun to germinate, 

 a flat plate-like expansion, 

 somewhat resembling a 

 heart in form, shows itself. 



Fig. 1(39. — Sorus of Depuria prolijera. 



This expansion gradually 

 thickens, the tube from which it had sprung w^ithering 

 away. So far, observes Mr. Henfrey, there is nothing very 

 remarkable in the development of these plants from their 

 spores, but the succeeding phenomena are exceedingly 

 curious. The main particulars are thus described by him : 

 " At an early period of the expanding growth of the leaf- 

 like product of the spore, termed the prothallium or 

 germ-frond, a number of little cellular bodies are found 

 projecting from the lower surface, which, if placed in 

 water when ripe, burst and discharge a quantity of micro- 

 scopic filaments, curled like a corkscrew, and furnished 

 with vibrating hair-like appendages, by the motion of 



