CHAMBERS'S INFORMATION FOR THE PEOPLE. 



order is NECESSARIA, because the florets of the 



Necessaria. 



disc, or centre of the flower, being all male, it is 



necessary that those 

 of the ray or margin 

 should be female, in 

 order that there may 

 be perfect seed pro- 

 duced. Example : 

 Calendula. The fifth 

 order is called SE- 

 GREGATA, because 

 the florets have each 

 its proper involucre. 

 All the plants in this 

 order are exotic herbs and under-shrubs, the globe- 

 thistle being the most common in British gardens. 

 XX. GYNANDRIA. This class contains plants 

 which have their stamens seated upon the pistil. 

 The class is divided into three orders ; the first, 



Segregata. 



Hexandria. Diandria. 



Monandria. 



MONANDRIA, having one anther seated on the 

 pistil, and comprises Orchis, Ophrys, Epipactis, 

 &c. In the second order, DIANDRIA, the flowers 

 have two anthers on the pistil ; to this belongs 

 the ladies'-slipper. The third order, HEXAN- 

 DRIA, containing plants which have six stamens 

 seated in the pistil, has only one genus namely, 

 the Aristolochta, or birthwort. 

 XXL MONCECIA. This class (meaning one 



Diandria. Monandria. 



household) consists of plants which have male and 



female flowers separate, but on 

 the same root such as the 

 bread-fruit tree, the Zannich- 

 ellia palustris, the maize or 

 Indian corn (Zea), the box, the 

 mulberry, the common nettle, 

 the Aucuba japonica, the Ama- 

 ranthus, the coco-nut and other 

 palms, Begonia, the chestnut, 

 beech, hazel, walnut, oak, pines 

 and firs, larch, cedar, cypress, 

 gourd, melon, and cucumber, 

 the poisonous manihot, the 

 castor-oil, and the cuckoo-pint 

 or wake-robin (Arum macul- 

 atum). There are ten orders, 

 distinguished by the number 

 and arrangement of the sta- 

 mens, &c. some of which are 

 illustrated in the wood-cuts. To 

 this class belong the Carices 

 or sedges, and also the Erio- 

 caulon septangulare. 



Triandria. 



Polyandria. 



Hexandria. 



Monadelphia. 



XXII. DlGEClA. This class is composed of 

 plants which have unisexual flowers, not on the 

 same, but on different individuals, such as the 

 screw-pine, the willow, poplar, crow-berry, date- 

 palm, candle-berry myrtle, sweet gale, spinach, 

 mistleto, hop, hemp, &c. The orders are dis- 

 tinguished by the number, &c. of the stamens, as 

 indicated in the following wood-cuts : 



Triandria. 



86 



Monandria. 



Hexandria. 



Pentandria. 



