The above form is given in preference to a mere enumeration of the Linnæan Classes as being more useful and instructive. It will at once be perceived that if it is wished to know what class any plant belongs to, we must in the first instance observe whether it has stamens or pistils; if it has neither, it is one of the Cryptogamia, and our point is ascertained at once. If it have stamens and pistils we are referred to No. 2, and, accordingly, as the stamens and pistils are, or are not, on the same flower, we are to turn to No. 3 or 4, and so on till we have completed our search. Such an analysis is of great practical utility. The number of each class in Linnæus' arrangement, is given at the end of each in a parenthesis.

C.

At the end of a chapter on the longevity of trees, in which M. De Candolle fully shows his grounds for concluding their ages to be what he has stated, he gives the following table of some of the most remarkable in the world.

"The Baobab (Adansonia digitata) is the most celebrated example of extreme longevity that has yet been observed with precision. It bears in its native country a name which signifies a thousand years, and contrary to custom, this name is short of the truth."*

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The following notice respecting this species of tree has been kindly furnished by a friend. Adanson's own statement concerning the Baobab, and his reasonings upon it, amount to this. He saw, in one of the two Magdalen Islands, two Baobabs, bearing European names, some of which were very distinctly

* De Candolle, Physiologie Végétale, tom. ii. p. 1003.

of the date of the 16th and 15th centuries,* and others somewhat confusedly ('assez confusément') of the 14th; years having effaced, or filled up the greater part of the characters. These were probably the same trees which Thevet mentions having seen in those islands, in his voyage to the Antarctic Seas in 1555, (in which, however, no notice is taken either of the size of the trees, or of inscriptions on them.) These characters were six inches at the utmost in length, and not so much as two feet in width, being about the eighth part of the circumference of the trunk, from which Adanson concluded that they had not been cut while the trees were young. Neglecting the date of the 14th century, and taking that of the 15th, which is very distinct, he holds it to be evident that, if these trees have been two centuries in gaining six feet in diameter, they would be at least eight in acquiring twenty-five feet. But experience teaches that trees grow rapidly at first, afterwards more slowly, and finally cease to increase in diameter, when the tree has attained the size usual to its species. Adanson knew from observation, that the Baobab in its first year, measured from an inch to an inch and a half in diameter; that at the end of ten years it reached a foot in diameter; and at the end of twenty, about a foot and a half. These data, he adds, are insufficient for any precise determination: he, therefore, limits himself to suspecting that the growth of the Baobab, which is very slow with relation to its monstrous size (of twenty-five feet diameter) must continue for several thousand years, and perhaps ascend to the time of

*It seems clear that Adanson, in speaking of the 14th, 15th, and 16th centuries, really means the 15th, 16th, and 17th, inasmuch as he in one place carefully reckons from the date of the 15th century to the year 1749, as a period of two centuries.

the deluge; so that we have good reason to believe that the Baobab is the most ancient of the living monuments which the terrestrial globe can furnish. These particulars are given in a 'Déscription d'un Arbre d'un nouveau genre, appelé Baobab, observé au Sénégal,' published by Adanson in the Mémoires de l'Académie des Sciences, for 1761, where he also states the circumference of the tree as reaching to sixty-five feet, or even seventy-seven and a half feet, making its diameter somewhat less than twenty-five feet. In his 'Voyage au Sénégal,' he speaks, p. 545, of having measured two trunks of sixty-five and sixty-three feet circumference; and again, p. 104, of two others measuring seventy-six and seventyseven feet; but it does not appear that these were the trunks on which the names were cut.

"The only certain way of discovering the age of trees of temperate and northern climates is by cutting them down, and counting their annual layers; but even this method becomes uncertain with respect to the trees of tropical countries, in which the layers are frequently very indistinct, and in which they are also, in some instances, repeated several times in the year.

"With respect to the Baobab, if its age be doubtful, its size at least has not been exaggerated. M. Perottet states, in the 'Flore de Sénégambia,' that Baobabs are frequently to be found measuring from seventy to ninety feet in circumference. He promises a memoir on their mode of growth, but the writer of this is not aware if he has yet published it.

"The subject of inscriptions in trees (originally cut through the bark, and having their woody portion covered up by successive annual layers), is a very curious one. It has been the subject of nu

merous memoirs, of which a list is given in the Catalogue of Sir Joseph Banks' Library."

Although England has no trees whose usual size can compete with that of the gigantic Baobab above mentioned, some of her yews and oaks are as worthy of record, and approach more nearly to it in dimensions, than is perhaps generally known or remembered. Evelyn, after mentioning several giants of the forests, both of his own and foreign countries, says,

"To these I might add a yew tree in the churchyard of Crowhurst, in the county of Surrey, which I am told is ten yards in compass; but especially that superannuated yew tree now growing in Braburne churchyard, not far from Scott's Hall, in Kent; which being fifty-eight feet, eleven inches, in the circumference, will bear near twenty feet diameter, as it was measured first by myself imperfectly, and then more exactly for me, by order of the late Right Honorable Sir George Carteret, Vice Chamberlain to his Majesty, and late Treasurer of the Navy; not to mention the goodly planks, and other considerable pieces of squared and clear timber, which I observed to lie about it, that had been hewed and sawn out of some of the arms only, torn from it by impetuous winds. Such another monster, I am informed, is also to be seen in Sutton churchyard, near Winchester."* In a note, the Editor of the Sylva (Dr. A. Hunter) gives the following account of a most remarkable oak, actually rivaling the Baobab in girth, it is accompanied by an engraving. "My ingenious friend, Mr. Marsham, informs me that there is now growing in Holt Forest, near Bentley, a vigorous and healthy oak, which at

* Sylva. Vol. ii. Book 3, Ch. 3, p. 195. Hunter's ed.