173 



From the sowing of the spore to the potting up of the 

 saleable plant, they are passing under the inspection of 

 expert discoverers, so to speak, and are not likely to escape 

 notice. 



The wild " sport," on the other hand, may originate in 

 the midst of myriads of its normal fellows on a wild hillside 

 far from the haunts of men, or in the deep recesses of a 

 wood where the chance of its discovery is just as remote 

 as under the opposite conditions described it is likely. 

 Since this experience has shown that despite this handicap 

 many hundreds of wild sports have been found, it is clear 

 that given a like percentage or per millage of variation 

 among the myriads of cultivated youngsters, it is no 

 wonder that a large amount of variation is discovered 

 among them, and it is by no means necessary to impute 

 this at all to cultural stimulus. 



Furthermore, a vast number of plants raised under 

 cultivation are from already abnormal parents, and 

 this, it is well known, tends to further variation. 

 Among British ferns, as we have indicated, the great 

 majority of sports under culture can be traced back to a 

 wild source, but among exotics one of the most striking 

 examples to the contrary is that of the innumerable forms of 

 Nephrolepis exalt ata, and other species, which have appeared 

 of late years, as derived from species which originally 

 appeared incapable of any marked variation. 



In N. exaltata we have, indeed, one of the most unpro- 

 misingly simple forms conceivable, a mere once divided 

 frond of plain sword-like outline, and yet when this once 

 began to become decompound, i.e. more than once divided, 

 it proceeded to vary, so to speak, by leaps and bounds, 

 producing by its thready stolons, and not as usual through 

 its spores, a succession of variants in the way not only 

 of finer and finer dissection, culminating so far in N. e. 

 WillmottcB and Mavshalli compatta, but also of different 



