96 NATURAL HISTORY BULLETIN. 



The following key has been improvised for the genera 



represented in Iowa: 



* Carpels 1-2-ovnled or sevzral-ovuled; fruit follicles or berries. 



f Flowers regular; leaves palmately nerved; petals wanting. 

 Hydrastis. Carpels ripening- into a head of red berries. 

 Caltha. Carpels ripening - into a head of dry follicles. 



ft Flowers regular; leaves ternately or pinnately compound or 

 decompound. 



% Petals not spurred. 

 Isopyrum. Flowers medium, white, solitary or panicled; fruit form- 

 ing follicles. 



CopTIS. Stemless herbs with trifoliolate leaves and umbellate 

 follicles. 

 Actaea. Flowers small, white, fruit forming berries. 



X\ Petals produced backward into hollow spurs. 

 Aquilegia. The only genus. 



fft Flowers irregular, posterior sepal spurred. 

 Delphinium. With us the only genus. 



** Carpels i-ovuled; fruit an achene. 



f Flowers involucrate. 



X Styles none or short and glabrous or pubescent. 

 Anemone. Involucre foliaceous, remote from the flower. 

 Hepatica. Involucre of 3 simple sessile leaves, calyx-like, close to 

 the flower. 



Syndesmon. Involucre of 3 compound sessile leaves, leaflets petiolu- 

 late. 



XX Styles elongated, densely plumose. 

 Pulsatilla. Involucre forming a cup. 



ft Flowers not involucrate. 



X Leaves opposite. 

 Clematis. Sepals petaloid: petals wanting. 

 Atragene. Sepals petaloid; petals small, spatulate. 



XX Leaves alternate or basal. 



% Sepals spurred. 

 Myosurus. Leaves basal, linear. 



§§ Sepals not spurred. 



A. Petals present. 



Ranunculus. Flowers yellow; achenes compressed, smooth. 

 Batrachium. Flowers white; achenes transversely wrinkled. 

 Oxygraphis. Flowers yellow; achenes compressed, longitudinally 

 striate. 



B. Petals none. 



Thalictrum. Leaves ternately decompound. 



Hydrastis canadensis L. Syst. Ed. 10, p. 1088. 

 1759. 

 This is a hairy vernal plant, about one foot high, springing 



