36 RANUNCULACEiE. 



Leaflets lobed. Petioles commonly auriculate-dilated at the 

 base, forming a small- stipuliform appendage on each side. 

 Flowers white or light yellow, small or middle-sized, ter- 

 minating the stem and branches. 



Etymology and Properties. A name given by Dioscorides to a Gre- 

 cian plant (probably Fumaria eapreolata), formed of 'Irros, equal, and irvpos, 

 wheat. Slightly acrid plants, of no known importance. 



Geographical Distribution. A genus of few species, sparingly scat- 

 tered over the northern temperate zone. The two North American species 

 are remarkable for being apetalous : that of the United States has just the 

 aspect of the European I. thalictroides, L. ; while the Californian species is 

 more like the Siberian I. fumarioides, L. Two other species belong to the 

 Altaic and Himalayan Mountains, and a seventh to Japan. 



Note. The analyses in Plate 12 having been made from dried speci- 

 mens, with aid of a former sketch in which this point was not particu- 

 larly attended to, we are not sure that the raphe is correctly represented as 

 ventral ; but the ovules, which are only two or three in number, are certain- 

 ly superposed in a single series. 



PLATE 12. Isopyrum (Enemion) biternatum, Torr. <J- Gray; — plant 

 from Ohio (Sullivant), of the natural size. 



1. A stamen, magnified. 



2. The pistils, on the receptacle, magnified. 



3. Vertical section of a pistil, magnified. 



4. Pistils in fruit, the ripe follicles divaricate ; enlarged. 



5. A seed, magnified ; showing the thick raphe. 



6. Vertical section of the same, displaying the embryo at the base of the 



albumen. 



