598 



BOTANY. 



sands of Africa, and from under the snows of Siberia 

 The first is by far the largest order, containing nine 

 tenths of the whole class. 



The second order, DIGYNIA, contains only three 

 genera, but one of them is most important to the in- 

 habitants of tropical countries, and to those of the 

 warmer parts of the temperate zones. Rice is the 

 staff of life in India, and is cultivated on every spoi 

 of level ground where there is a command of water 

 for irrigating the crop. Its quality as a grain is highly 

 nutritious, and at the same time easily prepared for 

 use. A wooden pestle and stone mortar is only 

 necessary to free it from its rough husk ; and whe 

 winnowed, simple boiling with the addition of a little 

 salt prepares it as a principal article of food for both 

 rich and poor. This plant is a true cereal, and has 

 been properly placed by Jussieu among the grasses 

 The only British plant in this order is the Oxyria 

 reneiformis, mountain sorrel. 



The third order, TRIGYNIA, contains a few bulbous 

 and tuberous stemmed plants, as the birds' tongue 

 the elegant trillium, and the meadow saffron, a 

 common English plant, as well as the well-known 

 dock. 



The fourth order is POLYGYNIA, comprising only 

 four genera, among which we find one of the most 

 beautiful British genera, namely, the water-plantain. 

 It is only found in pools or turfy bogs, and if culti- 

 vated it must have a place in the aquarium. 

 Hexandria. 



Trigynia. Digynia. 



In studying the plants of this class care must be 

 taken not to confound them with those of the fifteenth 

 class (Tetradynamia), which also has six stamens. 

 The distinction is this : in Hexandria the stamens are 

 of equal length, whereas in the fifteenth class four 

 are longer than the other two. But besides, the 

 structure of the flowers of this latter class sufficiently 

 distinguish them from the former. 



The seventh class is HEPTANDRIA, and contains 

 four orders, which together comprise fifteen genera 

 and forty-eight species. The first order is the largest, 

 and contains two nearly allied genera of trees, viz., 

 the aesculus and pavia, better known by the name 

 horse-chestnut. They are among the most orna- 

 Heptandria. 



Digynia. Monogynia. 



mental of our forest trees, though they are not native 

 foresters. The flowers of the common sort are well 

 known, and one or two of the pavias have bright red 

 flowers, which are most striking objects in ornamental 

 scenery. The common horse-chestnut yields great 

 crops of nuts ; but except deer, no other domestic 

 animal will touch them. 



Order second, DIGYNIA, contains only one genus, 

 namely, the Limeum Africanum, a perennial herb 

 from the Cape of Good Hope. 



The third order, TETRAGYNIA, comprises only two 

 genera, Saururus, lizard's tail, and Astranthus, a new 

 genus lately introduced from China. 



Heptagynia. Tetragynia. 



The fourth order is HEPTAGYNIA, that is, plants 

 having seven stamens and seven pistils. It is re- 

 markable that among above three thousand genera 

 only one should occur with seven stamens and seven 

 styles ; indeed, as J. J. Rousseau says, nature has 

 neglected the number seven in her arrangement of 

 vegetable structure. 



Class eight is OCTANDRIA, which contains four 

 orders, seventy-seven genera, and one thousand and 

 fifty-nine species. Many beautiful plants are ranged 

 here ; of those the heaths are the most conspicu- 

 ous and numerous. Of this family alone there are 

 five hundred and forty-three species already de- 

 scribed, chiefly natives of the southern parts of 

 Africa. A few are found in Britain, and several in 

 other parts of Europe. The curious Rhexia, the gay, 

 and night-flowering (Enothera, and the elegant Fuch- 

 sia, are found in this class. So also is the well 

 known mezereon, and many exotic genera of great 

 beauty. 



The second order, DIGYNIA, contains only five 

 genera, all exotics, Weinmannia being the chief. 



The third order, TRIGYNIA, comprises nine genera, 

 among which the sea-side grape, and soap-berry of 

 the West Indies, are the most remarkable. 

 Octandria. 



Trigynia. Digynia. Monogynia. 



The fourth order, TETRAGYNIA, contains six genera, 

 among which is the curiously organised Bryophyllum, 

 which bears viviparous progeny on the edges of its 

 eaves. The two little interesting British plants, 

 Paris and Adoxa, are also placed in this class and 

 order. 



Tetragynia. 

 The ninth class, ENNEANDRIA, is furnished with 



