The nature of the forest varies a good deal with the exposure and with the quality of the soil. By far the greater part consists of an oak and a rhododendron, both small evergreen trees, rarely exceeding thirty or forty feet, with wide-spreading arms and rugged twisted branches. A species of Andromeda is also very common, and a holly, an Euonymus, Rhamnus, and Benthamia, are the other more common trees, if we except the Coniferæ, of which four species occur. Of these, Pinus longifolia is common at the western or lower extremity of the station, and prevails, to the exclusion of any other tree, on the dry sunny spurs which run towards the south, at elevations from 7000 to 5000 feet. This species is, of all the Indian pines known to me (except its near ally P. Khasyana), that which is capable of enduring the most heat, and at the same time the greatest variation in amount of moisture; as it is found at elevations of not more than 1000 feet above the level of the sea, equally in the hot humid valleys of Sikkim, where it enjoys a perpetual vapour-bath, and on the dry sandstone hills of the upper Punjab, on which rain hardly ever falls. It is only, however, at low elevations, where the mean temperature is high, that it is capable of supporting a great amount of humidity, for in the damp climates of the Himalaya it is entirely wanting, except in the deepest valleys; and even in the drier districts it is always observed to select the sunnier, and therefore warmer exposures. Its upper limit is usually about 7000 feet above the level of the sea, though on Jako at Simla a few stunted trees rise as high as 7700 feet.
Pinus excelsa is also a very common species at Simla, particularly on the southern face of Mount Jako, which is the highest part of the ridge. Abies Smithiana, the third coniferous tree, is exceedingly rare, a few trees only occurring in a shady ravine facing the west; while the deodar, the fourth species, is common on the southern and western slopes of Jako, above 7000 feet; and again in shady groves at the bottom of the valleys on both sides of the ridge, as low as 5000 feet. This beautiful tree, the cedar of the Indian mountains, seems limited to the western half of the Himalayan range, extending from the most westerly part of Nipal, as far as the mountains of Affghanistan. It was first described by Roxburgh from specimens sent to him from Kamaon, at a time when the western Himalaya was almost inaccessible to Europeans, under the name by which it is known to the inhabitants of that province, as well as in Kashmir. It is, however, singularly enough, not known by that name in the Simla hills, where it is called Kélu; another conifer, Cupressus torulosa, a rare tree in the district, having usurped the name, as well as the sacred character, of deodar.
In the thick woods of Simla, a large white monkey, the Langúr of the natives, is very common. These animals move about in large flocks, in which may be seen individuals of all sizes and ages, and seldom remain more than a few hours in one place. They are in constant motion, leaping from bough to bough and from tree to tree, chattering constantly; and, notwithstanding their great size, are in general harmless, though ready enough to defend themselves if assailed.
The forest extends in parts close up to the peak of Jako, which has an elevation of 8130 feet. The very summit, however, which is a short flat ridge, and a considerable part of the east and south face, are bare and grassy, or covered with scattered shrubs. The more common shrubby forms of the vegetation of the temperate zone, are Salix, Rosa, Rubus, Lonicera, Viburnum, Berberis, Indigofera, and Prinsepia, all, except the two last, quite European. Indigofera forms a remarkable exception, and one well worthy of note, as the genus is a very tropical one, although its shrubby species are particularly abundant throughout the whole of the western Himalaya. These shrubby species, however, constitute a particular section of the genus, very distinct in habit, and in the large size and bright colour of the flower, from the more ordinary forms, and they are confined to the drier parts of the mountains, being quite wanting in the humid climate of Darjeeling and Khasya, and almost entirely so in the mountains of the Peninsula.
VEGETATION OF THE SPRING MONTHS.
May, 1847.
The herbaceous vegetation of the spring months quite corresponds, in the temperate nature of its forms, with what has been found to be the case with the trees and shrubs; but during the rainy season, as has been well pointed out by Dr. Royle in his valuable essay on the distribution of Himalayan plants, this is much less markedly the case. At the commencement of spring, in April (for March is still too cold for much vegetation), the weather being generally bright, though with occasional heavy showers, the earliest flowers are species of Viola, Fragaria, Geranium, Veronica, Valeriana, and dandelion. From April, as summer advances, the temperature gradually rises, till towards the end of June, when the rainy season commences. These months are generally dry, and if no rain falls the heat is sometimes considerable, the thermometer rising as high as 80° in the shade. Still the flora is almost entirely temperate, the early spring plants being succeeded by many others of European families, principally Ranunculaceæ, Rosaceæ, Labiatæ, Stellatæ, Polygonaceæ, Epilobiaceæ, Primulaceæ, etc. I can scarcely enumerate a single spring flowering plant which does not belong to an European family, unless Arum be an exception, which it can hardly be considered, the flowers only being displayed during May and June, while the leaves do not make their appearance until after the rainy season has commenced. Few species are, however, identical with those of Europe, except Stellaria media, Cerastium vulgatum, Taraxacum officinale, Verbascum Thapsus, Thymus Serpyllum, and Poa annua.
FLORA OF RAINY SEASON.
July, 1847.
PEAK OF JAKO.
July, 1847.
The rainy season generally commences about the 20th of June, or between that date and the end of the month, and continues till the middle or end of September, with occasional intermissions, rarely exceeding a week at a time. During the rains the atmosphere is exceedingly moist, dense fogs usually prevailing when rain does not fall. The rain-fall is probably more considerable at Simla than in the lower ranges, which are nearer the plains, for it has been observed that ranges of 7-8000 feet (which are generally for this reason well wooded), attract much moisture, and the peak of Jako and other parts of Simla are frequently observed from the stations of Sabathu and Kussowlee, to be covered with dense clouds or mist, at times when at the latter places the weather is bright and clear.
The commencement of the rainy season is the signal in the mountains, as it is very universally throughout India, wherever that season is well marked, for the appearance of a very vigorous and luxuriant growth of plants of annual growth, the seeds (or rootstocks) of which had been lying dormant in the soil awaiting the access of heavy rain. At Simla, as elsewhere in the temperate region of the Himalaya, we find at this season numerous species of Balsams, Acanthaceæ, Orchideæ, and Labiatæ, several Gentians and Cichoraceæ, a great many grasses and Cyperaceæ, and species of Parnassia, Drosera, Pedicularis, Roscoea, Dipsacus, Thalictrum, Urtica, etc., etc. Some of these are quite European genera, while others, as Roscoea, are interesting as belonging to orders whose maxima occur in very humid climates. The Labiatæ of the rainy season are mostly species of Plectranthus and Elsholtzia, both quite Indian genera, and very extensively distributed in mountainous districts. Balsams are quite an Indian order, and they seem everywhere, as has already been remarked by Dr. Royle and by Dr. Wight, to abound in humid shady places, either in dense forest or on the stony banks of mountain streams, in the drier districts only during the rainy season, but in more humid countries more or less throughout the year. The Orchideæ of Simla are entirely terrestrial, the dryness and cold of the winter months being greater than are compatible with the occurrence of epiphytical species of this natural order, and for the same reason, I presume, Melastomaceæ, so abundant in the Eastern Himalaya, are quite wanting.