FKRX CONFERENCE. 



507 



from a large plant of Asplcnium nidum ; this was done in the 

 autumn, and all the spring fronds came up crested. Spores from 

 these produced a crested variety. A change of circumstances with 

 a large number of varieties of Scolopendrium vulgare—i.e. planted 

 where the surroundings were not favourable — caused all of them 

 to return to the normal form of the species. Under pot culture 

 I have never found varieties to degenerate ; better soil, a more 

 avourable situation, and greater attention is a sufficient reason. 



At the Dundee meeting of the British Assx-iition in 18G7 I 

 pointed out that a certain law of form in the varieties of Ferns 

 seemed to be common to all species — crested, branched, revolved, 

 truncated, tortuose, brachiated, plumose, cruciate, linear, de- 

 pauperate in both fronds, pinnae and pinnules — and the manner 

 of these changes are common to all the species, and even the 

 multiple of these, the combination of several characters, such as 

 the linear-crested or cruciate-crested. In course of time we may 

 produce plants having many of these forms combined on the 

 same frond. 



Again, spores gathered from an abnormal portion of a frond 

 can reproduce this abnormality, whilst spores from a normal 

 portion of the same frond can produce normal plants. Also if 

 plants are raised from varieties for several generations, it is 

 almost impossible to obtain the original normal forms. 



The spores from crossed varieties are quite as proliferous as 

 that of the normal form, whilst hybrids — i.e. crossed species — are 

 all but sterile. There appears to be no absolute sterility. Take 

 the hybrid that I raised between the Aspidiums aculeatum and 

 angulare. A hundred pans of spores that I sowed did not produce 

 a single plant. Mr. CarbDnell, however, raised nine, and Mr. 

 Barnes thirty plants, ail of which differ from the parents and 

 hybrids, the grandchildren being more or less congested in 

 growth. With regard to Nephrodhim rcmotum, a hybrid between 

 spiiiulosum and filix-vias, repeated sowing of spores for more 

 than ten years did not produce a single plant, though by accident 

 Br. Stansfield has succeeded. 



At the British xlssociation meeting in 1870 I gave the 

 following additional results : — 



Spores from a normal frond produced only normal Ferns. 



Equal proportions of spores from a normal and from an 

 abnormal frond produced 90 per cent, of abnormal forms. 



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