"tne FLQRA OF A POTHOLE, 
Co. Ba WOU Mae, 
Oughtershaw Hall, Langstrothdale, Yorkshire. 
Few spots could supply more striking lessons in plant distribution 
than the little tract of moorland lying to the northward of Oughter- 
coarse Millstone Grit, in the crevices of which grows WVephrodium 
dilatatum. However, it is not the Grit but the Limestone which 
has led to the special feature of the spot in question ; there appears 
to have been a line of weakness running roughly north and south 
for several hundreds of yards where the solvent powers of the peaty 
waters have exercised a special sway, burrowing out underground 
hollows in the limestone or gradually enlarging fissures at the surface 
into ‘swallow holes,’ or the more dignified ‘potholes.’ Two or three 
of these latter are from some 15 feet deep, with rocky sides, or ove side 
rocky where the overflow from the neighbouring tarn trickles down 
and disappears in the subterranean fissures. It is these which 
present us with a profusion of plant life, a truly zzswdar flora 
surrounded by a sea of moorland. The latter of uniform soil, 
uniform elevation (some 1,800 feet above the sea-level), and uniform 
exposure to the stiff prevailing west wind, is clothed with a vegeta- 
tion as poor in its number of species as it is rich in its wealth of 
individuals. Ling and Bell-heather, Knoutberry, Bilberry and Cow- 
berry, the little white Rock Bedstraw, the Daisy and the Tormentil 
—the montane variety of the yellow Cow-wheat—grasses and 
sedges, not forgetting the Hare’s-foot Cotton Grass conspicuous 
against the peat bogs—these almost exhaust the list of the moor- 
land’s -plants.. But let us turn to one of the potholes. The Ling 
and most of its companions come no further than the brink: they 
at once give place to quite a different flora, amongst which we 
~ note :— 
Rumex acetosa, growing 300 ft. above its usual limit. 
Spirza ulmaria, 300 ft. above its usual limit. 
Geranium robertianum. 
Veronica chamzdrys. 
Stellaria holostea. | 
Epilobium angustifolium. E. montanum. 
fa 
Naturalist, ee 
