170 FERN GROWING 



are often quite distinct from the first crop. It must also 

 be understood that many Ferns do not assume their distinct 

 varietal character until they have become mature for several 

 years, and this more especially applies to the Aspidiums. On 

 the other hand, Ferns will show peculiar features when quite 

 in their infancy, these features becoming more and more 

 pronounced and improved with each unfolded frond. 



It is not known how long spores retain vitality. Some 

 that were gathered in 1887, ^.nd sown in 1893, showed life 

 in at least seventy per cent, of the spores. The late Dr. E. F- 

 Fox received spores from Dr. Allchin in 1873 ; these were sown 

 in 1892, and a number (although a much diminished number) 

 had retained vitality. 



The male sperms may not have much power in extricating 

 themselves from their cases, but they have some locomotive 

 force inter se, this is observed in the Vaucheria clavata, which 

 can stretch the walls of its confinement, and be squeezed 

 out, although much larger than the orifice of the tube in which 

 they are confined. This, however, is not a Fern. 



A few words should be said as regards sterile Ferns — those 

 in which there is an absence of any trace of sori, and those in 

 which there are only imperfect spores. A Scolopendrium 

 vulgare named sterile, found by Mr. J. Moly, is perfectly 

 sterile, and there is not a trace of sori ; it is normal in form, 

 of large size, but with somewhat thin fronds. 



The section crispum in Scolopendrium vulgare, with one or 

 two exceptions that are less crisp and bear sori infertile of Fox 

 is one), are all considered sterile, and until 1894 the author 

 had never seen any that did more than occasionally bear a few 

 solitary sori. However, last year Mr. Clutson, gardener to Mrs. 

 Cowburn, had a frond, in which the lower half was not only 

 copiously soriferous, but there were twice as many lines of sori, 

 and many of these were twice as long as usual ; they ended 

 suddenly in the middle of the frond, the upper half being 



