WHITE VARIETIES OF BRITISH PLANTS 147 



marked. White specimens of the purple knapweed are 

 not infrequently met with, and also of spear-thistle and 

 of the common centaury. The handsome red spur- 

 valerian has contracted a like habit, and a botanist of 

 the eighteenth century noticed some noble plants with 

 white flowers on the venerable walls of Winchester 

 Cathedral. Till within the last few years this variety 

 maintained its position on the south transept ; now, 

 while the normal red blossoms are conspicuous, the 

 white-flowering plants have disappeared. It used also 

 to flourish on the old walls of Yarmouth Castle, in the 

 Isle of Wight. 



It is, however, strange as it may seem, with the more 

 highly developed blue flowers that this reversion to 

 white is mostly seen. A notable instance is the sweet- 

 smelling violet, where in some districts, as in the neigh- 

 bourhood of Plymouth and in the Isle of Wight, the 

 white variety is the prevailing form. In springtime, 

 when the woods are carpeted with the wild hyacinth or 

 bluebell, it is nothing uncommon to find a few plants 

 with white flowers. In turning over the sheets of my 

 herbarium I noticed quite a large number of white 

 specimens of blue-flowering species. Among them 

 may be mentioned the hairbell, the nettle-leaved bell- 

 flower, the clustered bell-flower, the wild scabious, the 

 viper's bugloss and the autumnal gentian. The round- 

 headed rampion (Phyteuma orbicularia, L.), a choice 

 and striking species with deep blue flowers, sometimes 

 adopts the same habit. It is rare in Hampshire, but 

 it grows in several places on the downs and on Old 

 Winchester Hill, above the Meon Valley, where a white 

 specimen may occasionally be found. 



It is still more curious that this habit of relapse 



