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in animals than anything which had formerly been observed. . . . . The liquid, whose movement is described, and which M. Schultes terms the ‘latex,” is sometimes transparent and colorless, but in many cases opaque, and either milk-white, yellow, red, orange, or brown. . . . This liquid is considered to be the proper juice of the plant, secreted from the crude sap in the intercellular passages, and consequently analogous to the blood of animals, as was long since suggested by Grew ; who further likened the lymphatic, or crude sap, to their chyle. It is contained in delicate transparent membranous tubes, which become cylindrical when isolated, but when pressed together in bundles, assume a polygonal shape. . . . . The movement of the latex can be witnessed only in those parts which happen to be very transparent, and it has not been actually seen in many plants. The Ficus elastica, Chelidonium majus, and Alisma plantago, are the species upon which most of the observations hitherto recorded have been made. Distinct currents are observed traversing the vital vessels, and passing through the lateral connecting tubes or branches, into the principal channels. These currents follow no one determinate course, but are very inconstant in their direction, some proceeding up, and others down, some to the right and others to the left; the motion occasionally stopping suddenly, and then recommencing. . . . The effect does not seem to depend upon a contractile power of the tubes, because the latex flows chiefly or entirely from one end of a tube, even when it has an orifice open at both extremities. The appearance is especially analogous to the circulation of some of the lowest tribes of animals, as in the Diplozoon paradoxum, which may be divided into two parts, and the blood will continue to circulate for three or four hours in each. By a strong electric shock, the force by which the latex is propelled, is paralyzed, and its motion arrested.” (Henslow's Principles of Botany, p.

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1 Neither stamens nor pistils . . . . . . Cryptogamia (24.) Stamens and pistils . . . . . . . . . . 2. 2 (Stamens and pistils in separate flowers 3. All or many of the flowers perfect . . 4. Barren and fertile flowers on different 3 plants . . . . . . . . . . . . . . . . Dioecia (22.) Barren and fertile flowers on the same plants . . . . . . . . . . . . . . . . Monoecia (21.) Some flowers with pistils only, and a perianth unlike that of the united or of the barren flowers . . . . . . . Polygamia (23.) Flowers with both stamens and pistils, or with similar perianths . . . . . . 5. 5 Stamens situated upon the style . . . Gynandria (20.) Stamens not on the style . . . . . . . 6. 6 Flowers compound; (anthers 5, united) Syngenesia (19.) Flowers not compound . . . . . . . . . 7. 7 Filaments united in one or more sets 8. Filaments not united . . . . . . . . . 9. Filaments united in one set . . . . . . Monadelphia (16.) 8 Filaments united in two sets . . . . . Diadelphia (17.) Filaments united in more than two Sets . . . . . . . . . . . . . . . . . . Polyadelphia (18.) Stamens 16 or more . . . . . . . • 10. 9 Stamens 15 or fewer . . . . . . . . . . 11.

o 4Stamens inserted into the receptacle . Stamens inserted into the calyx . . . .

Polyandria (13.)
Icosandria (12.)

sStamens 12 or more . . . . . . . . . . Dodecandria (11.)

Stamens 10 . . . . . . . . . . . . . . . Decandria (10.)

11 Stamens 9 . . . . . . . . . . . . . . . Enneandria (9.)
Stamens 8 . . . . . . . . . . . . . . . Octandria (8.)
Stamens 7 . . . . . . . . . . . . . . . Heptandria (7.)
Stamens 6 or fewer . . . . . . . . . - 12.
Stamens 6 . . . . . . . . . . . . . . . 13.

12 & Stamens 5 . . . . . . . . . . . . . . . Pentandria (5.)
Stamens 4 or fewer . . . . . . . . . . 14.
Four stamens longer; (petals 4, rarely

1 wanting) . . . . . . . . . . . . . . . Tetradynamia (15.) Stamens equal (petals more or less

than 4) . . . . . . . . . . . . . . . . Hexandria (6.)

14 Stamens 4 . . . . . . . . . . . . . . . 15. Stamens 3 or fewer . . . . . . . . . . 16.

15 Two stamens longer . . . . . . . . . . Didynamia (14.) Stamens equal . . . . . . . . . . . . . Tetrandria (4.)

Triandria (3.)
Diandria (2.)
Monandria (1.)

Stamens 2 . . .

Stamens 3 . . . 16 Stamens 1

The above form is given in preference to a mere enumeration of the Linnaean 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 Linnaeus’ arrangement, is given at the end of each in a parenthesis.

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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.

Years. << Elm . - - - - . 335 Cheirostemon (a Mexican tree) . 400 (about) Ivy . - - - - - . 450 Larch . - - - - - 576 Lime - - - - - . 1147–1076 Cypress - - - - - 350 (about) Oriental Plane - - - . 720 and more Cranger - - - - - 630 Cedar of Lebanon . - - . 800 (about) Olive . - - - - - 700 (about) Oak - - - - - . 1500–1080–810 Yew . - - - • - 1214–1458–2588–2880 Baobab . - - - - . 5150 (in 1757) Taxodium (of Oaxaca) . - - 4000 to 6000 (about).”

“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.”*

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 sus

pecting 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 Adamson, 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.

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