110 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
British AND Earty Intropucep Exotic TREEs. 
The primeval forests of Britain are believed to have been 
mainly composed of Oak, Quercus Robur, and Scots Fir, Pinus 
sylvestris; the former predominating on the rich lands of the low 
country, and the latter on the poorer soils of the moors and 
exposed uplands. The remains of both are found in abundance, 
and often in a wonderful state of preservation, after the lapse of 
many ages, at the bottom of peat-bogs, which have grown up over 
them to a depth of many feet in the course of centuries. About 
a dozen other species of large trees, 30 or more feet in height, and 
with a stem of a foot or more in diameter at 5 feet up,—including 
Alder, Alnus glutinosa; Ash, Yraxinus excelsior; Beech, Fagus 
sylvatica; Birch, Betula alba; English Elm, Ulmus campestris ; 
Scots Elm, Ulmus montana; Hornbeam, Carpinus Betulus; 
Lime, Tilia ewropea; Poplar, Populus alba and others; Spanish 
Chestnut, Castanea vesca; Sycamore, Acer Pseudo-platanus ; 
Willow, Salix alba and others,—are considered to be indigenous, 
or have been introduced at such an early period that all record is 
lost of the date, and they are now as much naturalised in Britain 
ag any native tree. 
Of smaller British trees, indigenous or naturalised in far back 
ages, there is a greater number, and some of them produce timber 
of considerable value, beside being among the most useful and 
effective of ornamental and fruit-bearing trees. In this section 
are the Apple or Crab, Pyrus Malus; Aspen, Populus tremula ; 
Bird Cherry, Cerasus Padus; Box, Buus sempervirens; Buck- 
thorn, Rhamnus catharticus; Bullace, Prunus msititia; Elder, 
Sambucus nigra; Gean, Cerasus Avium; Goat Willow, Salix 
caprea; Guelder Rose, Viburnum Opulus; Hazel, Corylus 
Avellana; Hawthorn, Crataegus Oxycantha; Holly, Ilex Aqui- 
folium; Maple, Acer campestre; Medlar, Mespilus germanica; 
Pear, Pyrus communis; Plum, Prunus communis; Rowan, Pyrus 
aucuparia ; Sea-Buckthorn, Hippophe Rhamnoides ; Service-tree, 
Pyrus Sorbus; Sloe, Prunus spinosa; Spindle-tree, Huonymus 
europeus ; Strawberry-tree, Arbutus Unedo; White Beam, Pyrus 
Aria; Wild Service, Pyrus torminalis ; and Yew, Taxus baccata. 
Among the more notable indigenous or naturalised shrubs, 
the following may be mentioned :—Barberry, Berberis vulgaris ; 
Black Currant, Aibes nigrum; Bladdernut, Staphylea pinnata ; 
Bog Myrtle, Myrica gale; Broom, Cytisus Scoparius; Butchers’ 
