366 DIOECIA. 



6. Hexandria. No difference of stmcture is discernible 

 between the barren and fertile flowers of any genus 

 in this Order; witness Tamus, t. 91, though some- 

 thing to the contrary is mentioned in the Genera 

 Plant arum of Linnaeus. 



7. Polyandria. Under this Order I would certainly 

 comprehend all dioecious plants that have from 

 eight to any greater number of stamens, according 

 to the example set by Linnaeus himself in the last 

 Class. The genera are exceedingly variable in this 

 respect; and if all those, the accessory parts of 

 whose flowers are uniform, were taken away, the 

 remainder would be so few, that it is hard to say 

 whether any would remain at all. Instances of the 

 Order as it now stands are Populus, t. 16 J 8, 16 19; 

 Hydrocharis, t. 808 ; Mercurialis, t. 559. The 

 fertile flowers of the latter have, in some cases, a 

 nectary or corolla of two slender leaves, not found 

 in the barren ones, which may entitle it to a perma- 

 nent place here. Carica will also probably remain. 

 Rhodiola can scarcely be kept distinct from Sedum. 

 Coriaria and Ailanthus, having often united flowers, 

 are best in the tenth Class, asEuclea in the eleventh. 

 I find no genera truly icosandrous here, though 

 Schreber esteems Ftacourtia and Hedycarya to 

 be so. 



8. Monadelphia. Taxus, t. 746, and perhaps Jum- 



y t. 1 100, also the exotic Ephedra, are legiti- 



