1938 - The Vasculum

17
The first feature of the flora that strikes one is that the trees are
different, both in the hedgerows and in the woods. The woods lie on the
sides of the denes, and are composed not of oak, but of ash. The ash woods
are sadly ravaged by grazing animals which steadily destroy the
innumerable young seedlings, and prevent the old trees from being replaced
by young ones as the older ones die off. The trees can only hold their own
in the old quarries where grazing is prevented by the rocky ground, and in
such places the trees still flourish. Beneath the ash trees there is a dense
scrub of hazel and hawthorn, and a ground flora of wood sanicle and
woodruff. These ash woods are characteristic of the magnesian limestone
soils in Durham and they are also abundant on the Carboniferous Mountainlimestone
areas of Yorkshire. They correspond to the moist oak woods of
the non-calcareous soils, which prevail over most of Co. Durham and
Northumberland, and are fairly well displayed in the woods around Durham
City. The second feature of the flora is seen in the hedgerows. These look
familiar enough at first sight, but a closer inspection reveals several
differences as we pass from the non-calcareous to the calcareous soil. The
common hard head or knapweed (Centaurea nigra) becomes much less
abundant, and is replaced by the greater knapweed (C. scabiosa). The
common ragwort (Senecio Jacobaea) gives place to the cutleaved ragwort
(S. erucifolius) which has grey, hairy young leaves, but looks like a rather
straggling common ragwort in its older stages. The common wild violet is
supplemented by the hairy violet (V. hirsuta); the hedge parsley is
accompanied by the pepper saxifrage (Silaus pratensis) and climbing the
hedge is the black bryony (Tamus communis) with its strange dusky leaves
and scarlet fruits.
Most striking of all is the grassland flora where the soil is thin and
the limestone rock comes close to or actually reaches the surface. The
customary flora of thin, poor non-calcareous soil is ling, heather, matgrass,
bent grass and hair grass, but on the calcareous soil, these plants are
replaced by a different set. Quake grass (Briza media) is the common grass,
accompanied by another grass (Koeleria cristata), and an abundance of the
salad burnet (Poterium Sanguisorba), and the hoary plantain (Plantago