rage of the rainfall figures, 13 inches for Peshawar and
32 for Rawalpindi, would give a truer result. The monsoon rains come
later and are much less abundant than in the submontane zone. Their
influence is very feeble in the western and south-western part of the
area. On the other hand the winter rains, are heavier than in any other
part of the province. Delhi and Lahore represent the extreme conditions
of the central and south-eastern plains. The latter is really on the
edge of the dry south-western area. The eastern districts of the zone
have a shorter and less severe cold weather than the western, an earlier
and heavier monsoon, but scantier winter rains. The total rainfall
varies from 16 to 30 inches. The south-western zone, with a rainfall of
from 5 to 15 inches, is the driest part of India proper except northern
Sindh and western Rajputana. Neither monsoon current affects it much. At
Multan there are only about fifteen days in the whole year on which any
rain falls.

CHAPTER VI

HERBS, SHRUBS, AND TREES

~Affinities of Panjab Flora.~--It is hopeless to describe except in the
broadest outline the flora of a tract covering an area of 250,000 square
miles and ranging in altitude from a few hundred feet to a height 10,000
feet above the limit of flowering plants. The nature of the vegetation
of any tract depends on rainfall and temperature, and only secondarily
on soil. A desert is a tract with a dry substratum and dry air, great
heat during some part of the year, and bright sunshine. The soil may be
loam or sand, and as regards vegetation a sandy desert is the worst
owing to the rapid drying up of the subsoil after rain. In the third of
the maps appended to Schimper's _Plant Geography_ by far the greater
part of the area dealt with in this book is shown as part of the vast
desert extending from the Sahara to Manchuria. Seeing that the monsoon
penetrates into the province and that it is traversed by large snow-fed
rivers the Panjab, except in parts of the extreme western and
south-western districts, is not a desert like the Sahara or Gobi,
and Schimper recognised this by marking most of the area as
semi-desert. Still the flora outside the Hills and the submontane
tract is predominantly of the desert type, being xerophilous or
drought-resisting. The adaptations which enable plants to survive in a
tract deficient in moisture are of various kinds. The roots may be
greatly developed to enable them to tap the s