CLASS ENNEANDRIA. 99 



a 1-seeded, and mostly, angular nut. The stamens, 

 however, according to the species, are either 5, 6, 7, 

 or 8. In the P. virginianum, indeed, the flowers are 

 only 4-cleft, have but 5 stamens, and 2 styles. But 

 what the nature and extent of abortion is in this ge- 

 nus is not quite so certain as in Tropteolum, for in our 

 next genus, of this same natural order Polygoneje, 

 belonging to 



ENNEANDRIA 



Rheum, or Rhubarb, and also of the 3d artificial 

 order trigynia, the perianth, for there is but the one 

 floral envelope, is divided into 6 divisions, with the 9 

 stamens disposed in 2 series, of 6 and 3. The fruit 

 is, also, a triangular, thin nut, with winged margins. 

 In all the species, the leaves, resembling those of the 

 Dock, are very large and heart-shaped, and the thick 

 petioles of one species (R. rhaponiicum) are com- 

 monly cultivated for pies. The Rheum palmatum, 

 or medicinal Rhubarb, has scarcely any thing of an 

 acid taste, and palmated or 5-pointed leaves. Nearly 

 allied to this genus is the 



Eriogonum of the southern and western states, as 

 far as the Rocky Mountains. These have all small, 

 downy, oblong leaves, in radical clusters, or whorls ; 

 and the flowers whitish or yellow, disposed in umbels, 

 each partial cluster is surrounded by an inversely 

 conic cup, or involucrum. The flowers themselves 

 are those of Rhubarb, but downy, being 6-parted, 

 the stamens also 9 ; but the triangular seed or nut, 

 like that of Buckwheat, though narrower, is destitute 

 of the winged margins the seeds of the Rhubarb. 



Another remarkable genus of shrubs and trees be- 

 longing to the 9th class is Laurus, having mostly a 

 6-parted calyx ; a nectary consisting of 3 glands sur- 



