that, as we ascend lofty mountains like those of the Himalaya, we pass through belts or regions of vegetation of different types. The air steadily becomes rarer and therefore colder, especially at night, and at the higher levels there is a marked reduction in the rainfall. When the alpine region, which in the Himalaya may be taken as beginning at 11,000 feet, is reached, the plants have as a rule bigger roots, shorter stems, smaller leaves, but often larger and more brilliantly coloured flowers. These are adaptations of a drought-resisting kind. ~Regions.~--In this sketch it will suffice to divide the tract into six regions: Plains 1. Panjab dry plain. 2. Salt Range and North West Plateau, from the frontier to Pabbi Hills. 3. Submontane Hills on east bank of Jhelam. Hills 4. Sub-Himalaya, 2000-5000 feet. 5. Temperate Himalaya, 5000-11,000 feet. 6. Alpine Himalaya, 11,000-16,000 feet. Of course a flora does not fit itself into compartments, and the changes of type are gradual. ~Panjab Dry Plain.~--The affinities of the flora of the Panjab plains south of the Salt Range and the submontane tract are, especially in the west, with the desert areas of Persia, Arabia, and North Africa, though the spread of canal irrigation is modifying somewhat the character of the vegetation. The soil and climate are unsuited to the growth of large trees, but adapted to scrub jungle of a drought-resisting type, which at one time covered very large areas from the Jamna to the Jhelam. The soil on which this sparse scrub grew is a good strong loam, but the rainfall was too scanty and the water-level too deep to admit of much cultivation outside the valleys of the rivers till the labours of canal engineers carried their waters to the uplands. East of the Sutlej the Bikaner desert thrusts northwards a great wedge of sandy land which occupies a large area in Bahawalpur, Hissar, Ferozepur, and Patiala. Soil of this description is free of forest growth, and the monsoon rainfall in this part of the province is sufficient to encourage an easy, but very precarious, cultivation of autumn millets and pulses. The great Thal desert to the south of the Salt Range between the valleys of the Jhelam and the Indus has a similar soil, but the scantiness of the rainfall has confined cultivation within much narrower limits. Between the Sutlej and the Jhelam the uplands between the river valleys are known locally as Bars. The largest of the truly indigenous trees of the Panjab plains are the _farash_ (Tamarix articulata) and the thorny _kikar_ (Acacia Arabica). The latter yields excellent wood for agricultural implements, and fortunately it grows well in sour soils. Smaller thorny acacias are the _nimbar_ or _raunj_ (Acacia leucophloea) and the _khair_ (Acacia Senegal). The dwarf tamarisk, _pilchi_ or _jhao_ (Tamarix dioica), grows freely in moist sandy soils near rivers. The scrub jungle consists