Natural Habitats and Nativeness. 99 
Let that be as it may. The close pasture has conquered all 
the pit which was originally 12 feet deep, with the exception of 
the steep slope of its former face. There with difficulty, but 
greatly aided by the incline, the following species still retain a 
foothold. 
Alchemilla arvensis, Bursa pastoris, Cerastium arvense, 
_Erophila vulgaris, Geranium molle, Stellaria media, Trifolium, 
_ dubuim, Trifolium striatum, Veronica arvensis. 
Of these species, Bursa is not quite typical, or perhaps I should 
‘say it is the sandy pasture form, purple stalked instead of green, 
with purple sepals, and purple white petals. Tvifolium dubuim 
‘is the native wild plant, and not the seedsman’s variety. T. striatum 
is a rare plant in Lincolnshire. It has only been recorded on 
eight other occasions. Its nearest localities known being 16 miles 
off in a bee line on the west, and 18 on the east. 
It might be urged on the lines that Mr. Dunn argues in his 
“ Alien Flora,” that man—perhaps Neolithic man—formed this 
pit for his barrow material, and gave all these species a foothold. 
Consequently they are “alien” in the Watsonian sense. This 
much is allowed, and anything else in reason. For instance that 
the Priory people after 1173—long after, if any one requires it— 
used the pit. Ask anything in justice, and it shall be willingly 
conceded. Still the extremest case is given away. 
The pit has not been used for ages; that must be clear to any 
0 ologist, soil student, or botanist, who studies it. Then why 
lave these species retained their hold so long despite the all- 
sonquering turf around? Stock, rabbits, and birds seeking grit 
stones, have all helped to keep little broken patches on the slope 
of the old working face. The spot was called Rook-island in the 
rernacular before 1173, and these birds still breed in the next 
ultivation is only of “ medium or fair quality.” It is what is 
ocally called a “ holding pasture ;” one that can grow the bone 
and muscles of young stock well, but which cannot fatten them, 
