But making all allowance for these various disturbing influences, there are found in our flora certain plant groups which will not fit in with this general conception of immigration from the east. Let us take a few examples. In fir woods in Dorset, until some forty years ago (when it was exterminated), grew a slender little plant allied to the Lilies, too little known to have a popular English name, and called by botanists _Simethis planifolia_ or _S. bicolor_, the latter name having reference to the fact that the flower is purple on the outside, white on the inside. This plant is unknown elsewhere in Great Britain, and was at first set down by H. C. Watson, the leading British plant geographer, as an alien or denizen, not a true native; but the fact that it grows over a considerable area of very wild ground in Kerry (its only Irish station), far from possible sources of introduction, and undoubtedly native, indicates a strong probability of the plant’s having been indigenous in Dorset also. It is not present on the adjoining parts of the Continent, but turns up again in the Pyrenean region, some 500 miles to the southward, and may be traced thence into Italy and North Africa. Did this instance of an apparent migration from the south stand alone, it might not excite much attention, and we should probably be inclined to attribute the plant’s peculiar and discontinuous distribution to the extinction, perhaps by human agency, of intermediate stations. But it stands by no means alone. In Cornwall two [Illustration: FIG. 28.--GREAT BUTTERWORT (_PINGUICULA GRANDIFLORA_). [_To face p. 173._]