WOODLANDS 269 
The scar-woods of the limestone-dales of the Pennines 
are hazel-thickets, with ash as an occasional or frequent 
associate. Mountain-ash, hawthorn, holly, sloe, buck- 
thorn, dogwood, elder, wayfaring-tree, and privet also 
occur, the first three being the most common. Plenty of 
light penetrates to the soil, and the ground-vegetation is 
rich and varied. Many plants of the limestone-cliff are 
present (see p. 290), as well as shade-loving forms. The 
latter include Sanicula europea (wood-sanicle), Asperula 
odorata (sweet woodruff), Lathrea squamaria (toothwort), 
Mercurialis perennis (dog’s-mercury), Paris quadrifolia 
(herb-paris), Scilla nutans (wild-hyacinth), and several 
very rare plants—e.g., Polemonium ceruleum (Jacob’s- 
ladder), Cypripedium Calceolus (lady’s-slipper orchid, now 
almost extinct), Polygonatum officinale (Solomon’s-seal), 
and Convallaria majalis (lily-of-the-valley). 
The following classification of deciduous woods is that 
adopted by Moss, Rankin, and Tansley.* 
A. The Alder-Willow Series. 
Dominant trees: Alnus glutinosa, Salix cinerea, and 
S. Caprea. Found in very wet places, by marshes, streams, 
and in fens (see p. 243). 
B. Woods on Non-Caleareous Soils. 
I. Oak-Woods—(a) Lowland Type.—The damp oak- 
wood occurs on clays, loams, moist sands and gravels, 
and clay-with-flints (covering large parts of the chalk- 
downs of south-eastern England), up to about 600 feet. 
It is most common in valleys and on alluvial plains rich in 
humus. The trees are more luxuriant than on the up- 
lands, and they cast a deeper shade. The herbaceous 
ground-vegetation consists, therefore, either of shade-plants 
or early flowering perennials, which bloom before the 
trees are laden with foliage. Although the oak is domi- 
nant, many other trees are present, and in some places 
compete with the oak for dominance—e.g., ash, birch, 
hornbeam. The ash is typicaily a tree of the limestone, 
but it is common in damp lowlands as well, especially on 
* “The Woodlands of England,” New Phytologist, vol. ix., 1910, 
p. 113. 
