gorges, just above the sea-line; and the loose and tolerably fertile soil accumulated there consists of scoriæ mixed with sand, and the detritus washed from the rocks above by the torrents which rush down every ravine after the rare but heavy falls of rain. Along the cliffs utter sterility reigns, except where a ledge of rock or a mass of cinder has allowed the accumulation of sufficient earth to afford sustenance to a few straggling bushes of Capparis galeata or Adenium obesum.

"In so low a latitude, the sun shines with intense force nearly throughout the year; and at Aden the solar power is increased by every peculiarity of physical conformation and climate. The undisturbed åtmosphere stagnates in the walled-in valleys, where a deathlike stillness always reigns. The black and naked rocks absorb by day the scorching rays transmitted through an ever cloudless sky, only to radiate the pent-up heat by night, thus confining to the shore the cool but feeble breezes that occasionally spring up from the Indian Ocean. Accordingly, even in December, when the sun's power is at its lowest, Dr Hooker found the temperature of the soil at 107° Fahr, a few feet below the surface. In the hotter seasons of the year, the sun, even in the early morning, is overpowering, and above the rocks the air flickers from the intense heat, while all distant objects are distorted by an imperfect mirage. Almost perpetual drought is of necessity the concomitant of such a climate as I have described; and accordingly the annual rainfall at Aden never exceeds six or seven inches, this scanty amount being spread over the period between October and the end of April, while occasionally none falls for a year and a half. Still, Aden is not considered unhealthy, even to Europeans, who seem to become soon accustomed to the heat; and so great is our power of adaptation to circumstances, that after a residence of a year or two, the climate is spoken of as cool and pleasant from October to the end of March, and as bearable during the remainder of the year.

"The vegetation of Aden closely resembles that of Arabia Petræa, of which it is evidently the southern extension. It is eminently of a desert character, the species being few in number (only ninetyfour), and being quite disproportioned to the number of genera and natural orders, even when the flora is compared with those of localities having similar areas and similar relations to the mainland. Most of the species are limited in the number of individuals, a few only of the more arid forms predominating. Dipterygium glaucum, six or seven species of Capparidaca, Reseda amblyocarpa, Cassia pubescens and obovata, Acacia eburnea, and a few Euphorbiacea, are the only common plants; and some of thee are so plentiful that in many places they abound to the exclusion of all other plants. The other species are either very local, or sparingly scattered over the peninsula.

"All the species are more or less peculiar in their habits; and

some are so strange in their appearance as to constitute the anomalies of the natural orders to which they belong. As examples may be enumerated-Sphærocoma Hookeri among Caryophyllacea; Adenium obesum, with its almost globular fleshy trunk, naked branchlets bearing a tuft of leaves and an umbel of beautiful flowers; Moringa aptera, in which the leaves are reduced to long subrigid raches; the prickly Jatropha spinosa, and, strangest of all, the Eluropus arabicus, a grass with short spiny leaves, so sharp that it was with the greatest difficulty I could procure specimens of it. The bright green colour, which forms so pleasing a feature of the vegetation of the temperate and moist tropical regions of the globe, is quite unknown at Aden. Here foliage is reduced to a minimum, and the superfluous moisture given off by leaves in less arid climates is stored up in fleshy stems against seasons of long-continued drought. With the exception of some Capparidacea and Reseda amblyocarpa, all the plants have either glaucous whitened stems and leaves, or are completely covered with a hoary pubescence.

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Aridity, while reducing the amount of cellular tissue, has also favoured the production of spines; and though in many cases the development has not attained actual spinosity, still the rigid or distorted branches, and asperities of stem and leaf, bear witness to the modifying influence of the climate. Of the ninety-four species that constitute the flora, sixteen bear sharp thorns on some part of their structure. In some the leaves terminate in sharp, recurved hooks; in others the stipules are spinous; in a few the bracts are prickly; and in Lycium Europæum and Euphorbia cuneata, the short, stiff branches are terminated by short thorns. Several species yield gums or resinous matter, and their stems frequently become encrusted by these exudations, probably caused by the bark cracking from exposure to the great heat of the sun. I have observed resinous substances accumulated in various quantities on Balsamodendron opobalsamum, Acacia Edgeworthii, Adenium obesum, and the shrubby Euphorbia. All the Capparidacea (with the exception of Marua Thomsoni), Dipterygium glaucum, Reseda amblyocarpa, the Composite, and a few others, are characterised by more or less pungency or aromatic odour, qualities always possessed by plants of desert regions.

"Of the ninety-four species composing the florula, fourteen, or a little less than a sixth, are endemic, and one constitutes a new genus confined to Aden. They are as follows:

Cleome paradoxa, R. Br.

pruinosa, T. Anders. Marua Thomsoni, T. Anders. Sphærocoma Hookeri, T. Anders. Hibiscus Welshii, T. Anders. Sterculia arabica, T. Anders, Tavernieria glauca, Edgew.

:

Acacia Edgeworthii, T. Anders.
Ptychotis Arabica, T. Anders.
Convolvulus sericophyllus, T. Anders.
Anarrhinum pedicellatum, T. Anders.
Campylanthus junceus, Edgew.
Lavandula setifera, T. Anders.
Euphorbia systyla, Edgew.

The remaining eighty species have an extensive geographical distribution, fourteen occurring over all the barren part of the globe."

The work is executed with great ability. The character of the genera and species are well given, and the synonymes are worked out most carefully. It reflects the highest credit on Dr Anderson, and stamps him as one of the rising botanists of the age.

Flora of Cambridgeshire; or a Catalogue of Plants found in the County of Cambridge, with references to former Catalogues, and the Localities of the rarer Species. By CHARLES CARDALE BABINGTON, M.A., F.R.S., F.L.S. John Van Voorst, London 1860. 12mo, pp. 327.

No one has done more than Mr Babington to advance the study of British plants. His "Manual of British Botany" has long been a standard work, and is the most compendious fieldbook for the botanical student. The present volume contains a list of the plants of Cambridgeshire, with a description of the topographical peculiarities of the county, and a tabular view of the geographical distribution of species. The list contains about 950 flowering plants and ferns. A map is added, showing the different botanical districts into which the county may be conveniently divided. Ray published a list of Cambridgeshire plants about 200 years ago, and his work was succeeded by "Relhan's Flora Cantabrigiensis," the last edition of which appeared about 40 years ago. There was great need, therefore, of a new list brought up to the state of science at the present day. This has been most ably accomplished by Mr Babington. His valuable local Flora ought to be in the hands of every one who desires to know the plants of Cambridgeshire.

"The county of Cambridge is about 50 miles in length from north to south, and its greatest breadth is 25 miles. It is said to contain nearly 550,000 acres. It lies wholly between the 52d and and 53d parallels of latitude, and the town of Cambridge is situate five miles to the east of the meridian of Greenwich. We learn from the observations of the Rev. L. Jenyns, that the mean temperature of the seasons is-Spring, 47° 18 Fahr.; Summer, 60°.87; Autumn, 49°86; and Winter, 38°.09. The mean annual range

of the barometer is 1.890 inches. The mean fall of rain is about 22.5 inches. Deep drifting snow is not common, so that the roads are seldom obstructed by it. The prevalent winds are from the south-west and north-west; but cold north-easterly winds are very common in April and May. The highest part of the county is 378 feet above the level of the sea.' There are three marked divisions of the county--the Chalk, the Clay, and the Fens, which are each characterised by their flora. An appendix to the work

contains remarks on certain obscure species, a list of plants found on the Fens, a list of lost plants, and notes on the geographical range of the plants.

Flora of Suffolk; a Catalogue of the Plants (indigenous or naturalised) found in a Wild State in the County of Suffolk. By the Rev. J. S. HENSLOW, M.A., Professor of Botany, Rector of Hitcham; and EDMUND SKEPPER, Bury St Edmunds. Simpkin & Marshall, London, 1860. 12mo, pp. 140.

This useful catalogue has been compiled from lists and notes furnished by various persons who have examined the botany of different parts of Suffolk. We are informed that Mr Skepper has the entire merit of having reduced these materials to order, and of having seen them through the press, while Professor Henslow's part in the work has been that of a consulting, but otherwise sleeping partner. The reverend Professor has for many years examined the botany of Suffolk, and he has been instrumental in leading others to follow his example. His efforts in this respect among the young of his parish have been long known. The botanical and horticultural lessons given at Hitcham have done much to improve the intellectual and moral character of the population, and to train their observing powers-leading them from nature up to nature's God.

The Professor remarks, "Having had some years' experience of the advantage of introducing botany as an educational weapon in a humble village school, I can strongly recommend it to all who are interested in raising the intellectual status of our village children. Whoever may be desirous of seeing the plan we have adopted at Hitcham, will find the children at their botanical exercises every Monday at three o'clock. I have gradually accumulated sundry memoranda, which I hope to find leisure before long to throw into shape, that others may be saved the mistakes I have made, and profit by the experience I have acquired." The catalogue embraces both the flowering and the flowerless plants of the county; the former being arranged according to Bentham's "Handbook of the British Flora." The number of flowering plants and ferns noticed is about 980.

Notices of recent Botanical Works.

Among botanical works recently published, or in the course of publication, we may notice the various colonial Floras; these have been undertaken by botanists of the highest eminence. They are

most valuable contributions to science, more especially to botanical geography. To the Colonies such works are of great importance, not merely by adding to the knowledge of their floral productions, but also by communicating information relative to medicinal and economical plants. In the Flora Capensis, by Professor Harvey and Dr Sonder, we have the commencement of a systematic description of the plants of Cape Colony, Caffraria, and Port Natal; while, in Harvey's Thesauras Capensis, there are figures and brief descriptions of South African plants, selected from the Dublin University Herbarium. Thwaites, the talented superintendent of the Botanic Garden at Peradenia, is publishing an Enumeratio Plantarum Zeylaniæ, or enumeration of Ceylon plants, with descriptions of the new and little known genera and species, and observations on their habitats, uses, and native names. In this work he is assisted by Dr Hooker. We wish much that the excellent Flora Indica undertaken by Hooker and Thomson could be completed. The materials are ready, and it only wants the patronage of Government to secure its publication, which would be a great boon to India. Now that the Colonial Office and Colonial Legislatures are aiding in the Floras of our colonies, we may surely entertain a hope that the vegetable productions of our Indian possessions will not be neglected. The Flora of the British West India Islands has been undertaken by Dr A. H. R. Grisebach, Professor of Botany in the University of Göttingen; and the Flora Hong-kongensis, a description of the flowering plants and ferns of the island of Hong-Kong, has just been completed by Mr Bentham. This little island, situated at the mouth of the Canton river, possesses a singularly rich and varied flora. The island is a rugged mountain ridge, running from east to west, having peaks which attain the height of 1700 to 1800 feet.

The Australian Flora is being illustrated by Dr Ferdinand Mueller, the able and indefatigable superintendent of the Melbourne Botanic Garden. One of his works is entitled Fragmenta Phytographie Australia; another is An Account of the Plants indigenous to this Colony of Victoria, with illustrations. The Floras of the Antarctic Islands, of Tasmania, and of New Zealand, have already been given to the world in the splendid works of Dr Hooker.

While the Botany of the Northern United States has been published by Professor Asa Grey, that of the Southern United States has been recently drawn up by Dr A. W. Chapman, who has described the flowering plants and ferns of Tennessee, North and South Carolina, Georgia, Alabama, Mississippi, and Florida.

The successful establishment of a Botanical Society in Kingston, Canada, will, it is hoped, lead to the publication of a Canadian Flora by Dr G. Lawson, Professor of Natural History in the Iniversity of Kingston.