ii5 



satisfied when a specimen is brought before his notice 

 that it is likely to remain so, and we have even heard 

 doubts expressed as to the existence of a really constant 

 form. The reason of this uncertainty lies in the fact that 

 this species and its varieties is peculiarly prone to assume 

 a decidedly yellow tint, sometimes with stripes or mott- 

 lings of the normal green colour, when something in the 

 soil or the environment disagrees with it, and as a rule this 

 phenomenon is noted in plants which are exposed to bright 

 sunshine. Recently we were shewn a considerable number 

 of very diverse varieties in the garden of Mr. W. B. Cran- 

 field, at Enfield Chase, nearly all of which were variegated 

 as described, and yet they all belonged to batches of 

 seedlings or divisions of the same varieties which had 

 been planted elsewhere, and were there all of the same 

 normal green colour without a trace of variegation. 

 None of them, however, were robust and healthy, and they 

 were all, like many associated other species in the sarrbe 

 plot, more or less out of condition, the soil having become 

 waterlogged and sour. Here obviously was conclusive 

 proof that variegation may be temporarily assumed when 

 soil or other conditions are unfavourable. On the other 

 hand, a large and very strikingly variegated but otherwise 

 normal Hartstongue, found by the writer in 1909 at 

 Staverton, in Devon, with most of the fronds of a bright 

 golden yellow throughout, and the rest more or less striped 

 or mottled, was growing in a most congenial position on 

 the low bank of a small stream, and by its large size and 

 development was obviously in perfect health. It was, 

 however, quite unsheltered from the sun, and when carefully 

 lifted, potted and placed under glass, although the following 

 season, it grew again to full size, not a trace of variegation 

 appeared. In this case then it was clear that the varie- 

 gation was induced by extra bright illumination rather 

 than by any other handicap to healthy growth. Variega- 

 tion of this class, which is solely due to local influence and 

 disappears under change of environment, cannot therefore 



