The long-impending snowfall visited London on the morning of February 13th - a fitting close to the somewhat long and severe winter, which has left its mark on vegetation, having destroyed much - probably more than is surmised at the present time - during the period of the blustering severity of its reign. While the snow fell, it was so still and calm that it lodged on the trees and shrubs, giving them the appearance of being covered with a dense foliage of the finest silver; and when the sun broke out and lighted on them, they had the further appearance of being mantled with blossoms of the purest white. By noon, the sun, now gathering force as the days lengthen, soon dispelled, to a great extent, the garb of silver thrown over the earth, and by the intensity of its beams speedily dismissed hoary winter from further participation in the scene. There is now much reason to anticipate a genial spring and a fruitful beneficent summer.

At last a bond fide exhibition of Gladioli is to be held, and the 17th of August in the present year is the date fixed for the display. A very good list of subscriptions has been furnished by the leading growers, and nearly .£70 will be distributed in prizes. Of this sum £20 is allotted to Continental growers. The following classes have been agreed upon, and we think a thoroughly good exhibition may reasonably be expected, should the season prove at all favourable, though it is scarcely possible the northern growers can compete thus early in the summer: -

For Foreign Growers

Class 1

36 Gladioli, cut spikes, distinct, £10, £6, £4.

For Nurserymen

Class 2

36 Gladioli, cut spikes, distinct (Prizes offered by His Grace the Duke of Buccleuch, and G. F. Wilson, Esq., F.R.S.), £7, £5, £3.

Class 3

Gladioli, 18 cut spikes, distinct (for exhibitors not showing in Class 2), £5, £3, £2.

For Amateurs

Class 4

12 Gladioli, cut spikes, distinct, £5, £3, £2.

Class 4 A

9 Gladioli, cut spikes, distinct, £3, £2, £1.

Class 4 B

6 Gladioli, cut spikes, distinct (for exhibitors not showing in classes 4 and 4 a), £2, £1, 10s., £1.

Class 4 C

4 Gladioli, cut spikes, distinct, being new varieties sent out in the autumns of 1868, 1869, £2, £1.

The classes numbered 5 to 11 in the original schedule for the meeting of this day have not been altered.

This exhibition will be held at South Kensington, in connection with the meeting of the Royal Horticultural Society fixed for the above-mentioned date.

From the Continent comes an announcement that will be specially interesting to botanists, and we should think the offer is one likely to induce a spirited competition, particularly so among the Continental botanists. It is as follows: A prize is offered by the Royal Belgian Academy for an essay "to fix, by new researches, the place to be occupied in the natural system by Lycopodium, Selaginella, Psilotum, Tmesipteris, and Phyloylossum" The prize is to be a gold medal with £24. The essay must be written in Latin, French, or Flemish, and addressed, prepaid, to M. Ad. Quetelet, the Perpetual Secretary, before 1st June 1871. The Academy requires the greatest exactness in quotations, and the pages as well as editions of works cited must be given.

There appears to be reason to hope that the whole of the Chiswick Gardens will not be abandoned by the Royal Horticultural Society. We learn that it is proposed to retain all that part of it on which the glass structures are placed, and it is hoped a good piece of ground southward of that; but the walled-in kitchen-garden, as well as that part occupied by the collection of ornamental trees, will be given up. So it is stated; as a matter of course, there is much uncertainty as to what is really to be done, but there is certainly too much reason to fear that in as far as illustrations of practical horticulture are concerned, we have seen pretty well the last of any attempts in that direction at Chiswick.

A bulletin just issued by the Society of Acclimatisation of Paris is extremely interesting for the pregnant information it gives in regard to the Truffle. It has been compiled by M. Chatin, and at the outside he intimates that the Truffle is spoken of in the Book of Genesis under the Hebrew denomination of dudain. How the Truffles are generated, is a question M. Chatin cannot quite settle. Always found at the roots of certain trees, it was supposed by some that the raw material was furnished by the juice of the leaves penetrating into the ground; but one day a Truffle was found under a tub which had caught the juices, and that theory was destroyed. Others pretend that Truffles are simply tubercles of the roots near which they are found; but they seldom adhere to these roots, and there is no continuity - so that theory cannot stand. Many persons maintain that the Truffle is a subterraneous fruit, or a gall due to the sting of an insect, like the Gall-Nut. But the insect has not yet been discovered, nor the gallery by which it would have to withdraw, after having deposited the necessary matter. It is true, however, that certain flies are found to hover over Truffle-beds, and the poachers prefer to watch them to taking out a dog or a pig to hunt.

As regards the cultivation of the Truffle, M. Chatin considers that we are still in the infancy of the art as regards this root, mentioned in Genesis. It has long been the practice to plant Acorns with the view of eventually finding Truffles; but the Acorns, says the writer, should be selected from Oaks under which Truffles have been found: the season, the soil, the site, should all be carefully chosen, and the Truffle-ground should not be disturbed after May. Oak and Chestnut leaves may be used as manure, and a little irrigation is not bad. Should a tree be cut down, the Truffles will sulk and leave the roots for years, if not for ever; and in fact will often vanish if any of the larger branches be meddled with. Another curious detail is, that as the trees grow, the Truffle circle formed round them widens, and moves further away. The mysterious connection between the tree and its satellites remains to be solved. As regards Truffle-hunting, the sow is preferred to the hog, as being more docile and having a finer nose. A good pig will scent Truffles at 50 or 60 yards, and will very quickly lay them bare; this done, some Acorns must be given to the animal, who will otherwise refuse to hunt any more.

A pig may be hunted from the age of two till he attains five-and-twenty, but it is at four years old that he possesses all his most brilliant qualities. In a good many departments dogs are used, and they are easily taught to hunt; some are trained to scratch up the Truffles, others merely to mark the spot. A dog takes as much interest in the pursuit of Truffles as of game, manifesting the greatest pleasure in coming across a good bed. For the most of the foregoing information we are indebted to the Paris correspondent of 'Land and Water.'

A somewhat interesting discussion is just being raised as to the origin of Viola cornuta, var. Perfection, which was exhibited at a meeting of the Royal Horticultural Society in September last by Mr Jobson, of Rotherfield Park, Alton, and awarded a first-class certificate of merit. Mr B. S. Williams, who purchased the stock of it for distribution, claims it as a seedling raised by Mr Jobson, Y. cornuta being one of its parents; and he publicly intimates that "no plants but those which come from this stock are true in character." All that Mr Williams states in praise of this superb Viola is well deserved by it, and there is no doubt but that it will prove an invaluable blue-flowered summer bedding-plant, supplying a brilliant mauve-tinted blue, much needed in gardens. Whether it will bloom early enough in the spring to be of service for spring-bedding, remains to be seen; we think the chances are against its proving of much service so early in the season. About its value there can be no difference of opinion; about its origin, much difference of opinion.

Singular to state, a Viola has been found in the Alton district, and especially about Salisbury, so similar to the Rotherfield Viola, that an identity is claimed; and certainly we could see no difference between them when placed before us for comparison. This Viola has been grown in the neighbourhood of Salisbury for several years, and a Mr George Smith not only states that it has been in his possession for some years, but that he can trace its history for several years prior to having it in his possession; and claims the merit of being the first person who introduced this plant to the public. This appears fatal to the claim set up by Mr Jobson that it is a seedling of his own. The Floral Committee at South Kensington saw flowers of the two Violas, and the general impression appeared to be that the two were identical, and the chairman of the Floral Committee put on record that they were the same. The two will no doubt be fully tested during the coming summer. Meanwhile we cannot but express our sympathy with Mr Williams in having purchased the Rotherfield stock, under a full conviction that it was only to be found there and nowhere else, and his now finding it stated that it is by no means so new, or so restricted in cultivation, as he had been led to believe.

The Salisbury Viola was most favourably noticed by a correspondent in page 144 of our last number.