242 
called vermin by the game-keeper are especially 
at home. 
It is probable that a certain amount of dis- 
persal of plants is effected by these animals, 
the pads of the fox being often filled with clay 
in which seeds may be carried forlong distances. 
Upon the spines of the hedgehog large fruits 
such as crabs may be transfixed, and burs may 
stick to them. 
Birds, especially in woodlands, act as carriers 
of seeds from one place to another. The hard 
seeds of fruits may be dropped after the soft 
exterior has been eaten. In the same way 
squirrels may disperse nuts, storing them and 
forgetting them. Woodpeckers and titmice 
are factors in a woodland to be considered, 
because they aid the destruction in time of the 
trunks, which they riddle with holes and expose 
to air and rain, causing them to rot. The 
innumerable interactions between plants and 
animals are full of material for study. 
Ancient Woodlands.—The antiquity of the 
woods and forests in this country is undoubted, 
but as yet little definite information is avail- 
able, from the absence of any clear evidence 
earlier than the deposits that just precede the 
Ice Age or the Cromer Forest bed. In addi- 
tion to the numerous other plants, some, as 
Trapa natans (Water Chestnut), denoting a 
warmer climate, there were remains of the fol- 
lowing frees: Elm, Oak, Beech, Hazel (rare), 
Alder, White Birch, and three species of Wil- 
low. These indicate the same type of wood- 
land that is met with in this country to-day. 
If one were to examine the flora of the earlier 
Oligocene or Eocene one would find that the 
climate was still warmer, and in the Bovey 
Tracey beds the giant or mammoth tree type 
of California, Cinnamons, Evergreen Oak, 
Fig, Laurel, and in the Bournemouth beds of 
the same age, Eucalyptus, Araucaria, Sequoia, 
Platanus, are found, indicating as warm a 
climate. 
Between these beds and the Cromer Forest 
bed we have no very clear connection, but Oak, 
Elm, and Poplar of allied species occur. The 
submerged forests around the coast belong to 
a later period than the Cromer Forest bed, and 
contain the present-day trees. 
The Peat beds of Scotland have two forest 
beds, the lower containing largely White Birch, 
whilst the upper contains Pine, and these lie 
over Glacial beds. In Norway there is a third 
forest bed of Spruce. Thus, whilst we are 
largely foiled by the influence of the Ice Age 
in determining the area and age of ancient 
woodlands, there are certain data which indi- 
cate that they are Preglacial. 
Tree Zones.—The influence of altitude upon 
plants varies in degree. The tree type is 
HINTS AND 
NOTES 
especially affected by altitude, and in a corre- 
sponding manner by latitude or climate. In 
the tropics the belts as the loftier mountains 
are ascended correspond with those which are 
observed as one travels from the Equator to 
the poles. Thus at the Equator there are wet 
jungles of palms and bananas, followed by 
Savannahs, 10 degrees north to 20 degrees. 
Between 20 degrees and 30 degrees the main 
deserts are met with. Then come the Steppes 
and woods, made up of evergreen trees be- 
tween 30 degrees and 45 degrees. 
The large deciduous forests range between 
45 degrees and 55 degrees, and it is in this 
zone mainly, the cold temperature zone, that 
the British Isles are included. Northward 
from 55 degrees to 65 degrees come the Pine 
forests of Norway and countries of the same 
latitudes, as Canada in North America. The 
frozen Tundras, all but treeless, come between 
65 degrees and 75 degrees. The everlasting 
snow lies north of this, and beyond the snow- 
line only mosses and lichens will flourish as a 
whole. 
In ascending a tropical mountain there are 
from sea-level to 4000 ft. tropical forests, from 
this point to 8000 ft. sub-tropical forests, and 
upward to 9500 ft. temperate deciduous forests. 
A zone of conifers comes next between 9500 
and 11,500, alpine shrubs between 11,500 and 
13,300, alpine herbs up to the snowline, and 
above it mosses and lichens. 
Woodland Habitats and Associations. — Habhi- 
tats in general may be wet or dry, rocky or 
not, upland or lowland. The wettest habitats 
(especially E, Anglia) are afforded by the 
Alder-Willow associations, where the scrub and 
ground flora is made up of such plants as 
Guelder Rose, Currant, Gooseberry, Meadow- 
sweet, Yellow Flag, Reed, &c., Bitter-cress, 
Kingcup, Figwort, Great Hairy Willow-herb, 
Tussock Grass, &c. The tree types are scat- 
tered, and the ground itself is open, allowing 
such large herbaceous plants to thrive. 
On clays and loams, sandy and siliceous 
soils, the trees are Oak, pedunculate and 
sessile, Birch, with other trees. The scrub 
and ground flora are very variable. The 
woodland may be close or open. On clays and 
loams the ground flora is largely gregarious, 
e.g. Bluebell, Bracken. On sandy soils more 
often there is a good deal of bare rock surface 
with deep soil elsewhere, giving a variety of 
habitats. The same applies to a Birch wood. 
Here also there are wide associations of grasses, 
such as Heath Hair Grass, Matweed, &c., and 
the heaths also form wide gregarious associa- 
tions. These habitats are largely upland, 
whilst the oak-woods are mainly lowland, the 
sessile Oak not growing above 1500 ft. as a 
