This mean temperature is considerably increased by descending to the
bed of the Lachen at 8000 feet, and diminished by ascending Tukcham
to 14,000 feet, which gives a range of 6000 feet of elevation, and 20
degrees of mean temperature. But as the climate and vegetation become
arctic at 12,000 feet, it will be as well to confine my observations
to the flora of 7000 to 10,000 feet; of the mean temperature, namely,
between 53 degrees and 43 degrees, the isothermal lines corresponding
to which embrace, on the surface of the globe, at the level of the
sea, a space varying in different meridians from three to twelve
degrees of latitude.* [On the west coast of Europe, where the
distance between these isothermal lines is greatest, this belt
extends almost from Stockholm and the Shetlands to Paris.] At first
sight it appears incredible that such a limited area, buried in the
depths of the Himalaya, should present nearly all the types of the
flora of the north temperate zone; not only, however, is this the
case, but space is also found at Lamteng for the intercalation of
types of a Malayan flora, otherwise wholly foreign to the north
temperate region.

A few examples will show this. Amongst trees the Conifers are
conspicuous at Lamteng, and all are of genera typical both of Europe
and North America: namely, silver fir, spruce, larch, and juniper,
besides the yew: there are also species of birch, alder, ash, apple,
oak, willow, cherry, bird-cherry, mountain-ash, thorn, walnut, hazel,
maple, poplar, ivy, holly, Andromeda, _Rhamnus._ Of bushes; rose,
berberry, bramble, rhododendron, elder, cornel, willow, honeysuckle,
currant, _Spiraea, Viburnum, Cotoneaster, Hippophae._ Herbaceous
plants* [As an example, the ground about my tent was covered with
grasses and sedges, amongst which grew primroses, thistles,
speedwell, wild leeks, _Arum, Convallaria, Callitriche, Oxalis,