We find the following in the 0hio Farmer: - "The Guava (Psidium Cattluanum.) - Editor Ohio Farmer. - Sir: I herewith send you a fruit of the Guava (Psidium). It was produced by a tree, in my greenhouse, treated with the ordinary care of the tenants of that establishment. As an eatable fruit, it is palatable, somewhat resembling our paw-paws, flavored with the strawberry. For ornament, it is equal to the orange and lemon, and, for both these purposes, it is worthy of attention by the amateur horticulturist. It is the fruit from which the Guava Jelly is manufactured. My tree, about three feet in height, has matured, this autumn, thirteen specimens of the size and perfection of the one before you. In the Transactions of the Horticultural Society Of London, vol. iv. page 316, is contained a beautiful colored plate of the Psidium Cattlyanum, the name under which X procured mine; but as the fruit of the one is of a deep livid purple, and the other a rich lemon yellow, the latter must be either a different species or variety. The former is said to be the only species which will ripen its fruit in a greenhouse; hence I infer that my specimen is a mere variety.

Truly yours, J. P. Kirtland".

Cleveland, Ohio, Nov. 13,1856.

We are pleased to hear of this; the fruit is valuable, and may be cultivated successfully at the South; in East Florida, the Psidium buxifolium is found near the River St. Johns, but it differs from all other species. The twig is round, covered with a gray bark, and, at near distances, marked with the cicatrices of opposite fallen leaves. The berry is blackish-purple, pear shaped, about the size of a cherry; internally, it is filled with horizontal rows of flat, subveniform, pale, bony seeds, with a narrow embryo curved into the form of a horseshoe. This species is nearly allied to the purple-fruited Guava, P. Cattleianum (not Cattly-anum, as the Farmer has it), scarcely differing in anything but the smallness of the leaves and the pyriform fruit, though the leaves of the purple Guava, besides being much larger, are also pubescent when young.

Most of the species of this genus are cultivated in the tropics for their fruit. The P. pyriferum, or Common Guava, bears a fruit about the size of a hen's egg, yellowish, with a peculiar odor; the pulp is rather firm, flesh-colored, agreeable, and aromatic. In the West Indies, it is highly esteemed by all classes, being eaten raw, as Br. Kirtland indicates, as a dessert, or formed into an excellent sweetmeat and Jelly.

Of the fruit of the Purple Guava, to which ours is so closely related, Lindley remarks: "The excellent flavor of its fruit, which is very like strawberries and cream, is far superior to either P. pyriferum, pomiferum, or polycarpon." Mr. Sabine remarks of the fruit of this species, that "it is juicy, of consistenoe much like that of a strawberry, to which it bears some resemblance in flavor".

Whether the Florida species may become valuable when cultivated, is uncertain, but, in a genus so generally interesting for their fruit, says Nuttall, the "experiment is worth making".

The Guava will now be sought as a useful ornament, like the Eugenia ugni, for its beauty and its fruit.

We possess, too, in Florida, a Eugenia, the dichotoma ot fragrans, an elegant and fragrant species not yet introduced. This genus was named in honor of Prince Eugene of Savoy, who was an encourager of botany, and possessed a botanic garden.

The origin of Cuba Bast is at length discovered. The substance known under this name has now become familiar to gardeners, in consequence of its general substitution for Russian matting in tying up plants; but nobody could make out what tree produced it. In vain was inquiry directed to quarters where information on such points might have been expected to exist. Sir William Hooker, by diligent inquiries, has ascertained that it is produced by a West Indian tree, described, yean ago, by Swartz under the name of Hibiscus clatus, and which seems to be nothing more than a variety of the common Hibiscus liliaceous. A full account of the discovery is given in the new number of the Journal of Botany, from information collected from Mr. H. Christy, Mr. Scharfenberg, and Mr. Wilson, the Superintendent of the Botanic Garden, Jamaica. There is, therefore, some hope that this useful material may now be sold at a lower price than it bears at present.