All of
them were of the purest white, with only one exception, which was a
plant with the bluish rays of the species, wholly reverting to its
general type. As the variety does not give such reversions when
cultivated in isolation, this sport was obviously due to some cross in
the former year. In the same way I tried the white Jacob's ladder,
_Polemonium coeruleum_ album in the neighborhood of the blue-flowered
species, the distance [202] in this case being only 40 meters. Of two
hundred seeds one became a blue atavist, or rather vicinist, while all
others remained true to the white type. The same was observed in the
white creeping thyme, or _Thymus Serpyllum album_, and the white
self-heal, _Brunella vulgaris alba_, gave even so much as 28% seedlings
with purple corollas out of some 400 specimens, after being cultivated
in close proximity to its parent-species. I have tried many other
species, but always with the same result. Such atavists only arise by
cultivation in the proximity of allied varieties, never in isolation.
They are not real atavists, but only vicinists.
In order to show this yet more clearly, I made another experiment with
the white selfheal. I had a lot of the pinnate-leaved variety with
purple flowers and somewhat stouter stems, and cultivated single plants
of the whiteflowering sort at distances that varied from 2-16 meters.
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