DECANDRLA. 147 



Decandria is a class of considerable extent, and contains 

 portions of several natural orders, of which the most import- 

 ant is the Leguminosa, or plants bearing pods without a lon- 

 gitudinal partition, as the Cassia, Bean, and Pea. Most of 

 the plants of this description, which fall within this class, are 

 ratives of the Cape of Good Hope, or New Holland ; and 

 many of them are highly ornamental. This class also in- 

 cludes the trees which produce Logwood and Mahogany, 

 articles of great importance in the arts and ornaments of life. 

 The beautiful genera, Kalmia, Rhododendron, and Andro- 

 meda, likewise belong here, as does the Dianthus, of which 

 the Carnation is a species 



ORDER I. MONOGYNIA. Stamens 10. Style 1. 



GENUS Cassia. This genus contains at least sixty species, 

 none of which, however, except the Senna, (Cassia orienta- 

 lis,) are of any considerable consequence. Of this genus 

 we have four or five species, growing wild in New England. 



GENUS Swetenia. Fig. 170. Mahogany tree. Tnis ge- 

 nus was named after Von Sweiten, who persuaded Maria 

 Theresa, Empress of Germany, to found the botanic garden 

 of Vienna. The Mahogany tree, (Swetenia mahogani,) is a 

 tree of the first magnitude, growing from 80 to 1 00 feet high. 

 The trunk is sometimes very large, being near the ground 

 four or five feet in diameter. The branches are numerous 

 and spreading. Leaves pinnate, in 

 four pairs, as in the figure : the leaf- 

 lets oblong ovate ; flowers in pani- 

 cles. Mahogany is preferred to all 

 other woods for certain kinds of 

 cabinet work, not only on account 

 of its beauty, but because it is not 

 liable to shrink and swell with the 

 variations of moisture and dryness, 

 like .most other woods. It grows 

 in the hottest parts of America, as 

 Cuba, Hispaniola, and the Bahama Isles. The best is said 

 to grow on rocks, where there is little nourishment, and a dry 

 soil, and to come from the bay of Honduras. 



What important tribes and genera are mentioned as belonging to this 

 class? In what respect is Swetenia an important genus ? Why is ma 

 hogany preferred to all other kinds of wood for cabinet furniture ? 



