334 TAXONOMY. 



drew a clear and practical distinction between natural and arti- 

 ficial classifications (663), and deferring all endeavors to make 

 the former available, except for genera, he devised a practical 

 substitute for it, as a key to the genera, viz. his celebrated 



672. Sexual System, or arrangement of the genera under arti- 

 ficial classes and orders, founded upon the stamens and pistils. 

 Although now out of use, this artificial classification has been so 

 popular and influential, and has left so deep an impression upon 

 the science and especially upon the language of botany, that it 

 needs to be presented. The primary divisions are the classes, 

 twenty-four in number. But the 24th class, Cryptogamia, con- 

 sists of plants which have not stamens and pistils and conse- 

 quently no proper flowers, and is therefore the counterpart of the 

 remaining twenty-three classes, to which the corresponding name 

 of Phanerogamia or, in shorter form, Phsenogamia (Phsenogamous 

 plants) has since been applied. These twenty-three classes are 

 characterized by certain modifications and associations of the 

 stamens, and have substantive names, of Greek derivation, ex- 

 pressive of their character. The first eleven comprise all plants 

 with perfect (i. e. hermaphrodite) flowers, and with a definite 

 number of equal and unconnected stamens. They are distin- 

 guished by the absolute number of these organs, and are desig- 

 nated by names compounded of Greek numerals and the word 

 andria (from dvrJQ) , which is used metaphorically for stamen, as 

 follows : 



Class 1. MONANDRIA includes all such plants with one stamen to the flower; 



as in Hippuris. 



2. DIANDRIA, those with two stamens, as in the Lilac. 

 8. TKIANDRIA, with three stamens, as in the Valerian and Iris. 

 4. TETRANDRIA, with four stamens, as in the Scabious. 

 6. PENTANDRIA, with five stamens, the most frequent case. 



6. HEXANDRIA, with six stamens, as in the Lily Family, &c. 



7. HEPTANDRIA, with seven stamens, as in Horsechestnut. 



8. OCTANDRIA, with eight stamens, as in Evening Primrose and Fuchsia. 



9. ENNEANDRIA, with nine stamens, as in the Rhubarb. 



10. DECANDRIA, with ten stamens, as in Rhododendron and Ealmia. 



11. DODECANDRIA, with twelve stamens, as in Asarum and the Migno- 



nette ; extended also to include those with from thirteen to nine- 

 teen stamens. 



673. The two succeeding classes include plants with perfect 

 flowers having twenty or more unconnected stamens, which, in 



12. ICOSANDRIA, are inserted on the calyx (perigynous), as hi the Rose 



Family ; and in 



la POLYANDRIA, on the receptacle (hypogynous), as in the Buttercup, 

 Anemone, Sfc. 



