23 PRACTICAL BOTANY. 



Order I Y. Tetragynia 4 styles to eacli flower. 



" Y. Pentagynia' 5 " " 



« YL IIexagynia 6 " " 



" YII. Heptagynia 7 " " 



" YIIL OCTOGYNIA 8 « " 



" IX. Enneagynia 9 " " 



" X. Decagynia 10 " " 



" XI. DODECAGYNIA 12 01' 11 " " 



" XII. PoLYGYNiA more than 12 " 



61. The number of stamens serves to establish tlie 

 orders of the 16th, 17th, 18th, 20th, 21st and 22d classes. 

 To find their orders we proceed as follows : If a plant be- 

 longs to Monaddpliia (XYI.), DiadelpMa (XYII.), or 

 Polyadelj>hia (XYIIL), we examine how many stamens 

 have gone to form the cluster, the tube, or the bundles of 

 stamens. In the class Monadelpliia we have the orders, 

 M. Pentandria^ Decandria, and Polyandria ; in Diadel- 

 pJiia the orders, D. Ilexandria, Octandria^ Decandria ; 

 and in the class PolyadelpJiia only one order, P. Polymi- 

 dria. 



In the class Gynandria (XX.) we meet with plants, as 

 Spiranthes, belonging to the Orchids, and Aristolochiaio 

 the Blrthicorts. Spiranthes has one stamen, and hence 

 belongs to Gynandria Monandria, Aristolochia, with G 

 stamens, belongs to Gynandria Hexandria. Of the Or- 

 chids there is only one genus, belonging to the second 

 order of Gynandria ; namely, Cypripedium. 



In the classes Monxcia and Dioicia we find nearly all 

 the orders represented, w^hicli are based on the number of 

 stamens, and in Monobcia also the order Syngenesia, with 

 the anthers united (in the Gourd family). 



When a plant is, polygamous, we ascertain whether it is 



