Cardamine 



Cruciferae 



499 



^33 

 Map 1026 



.arSamine parviflora 

 var. arenicola (Brftt.) 0. E. Schul z 



50 



Map 1027 



Dentaria laciniata Muhl. 



33 



Map 1028 



Dentaria multifida Muhl. 



This species, like the next, prefers denuded or semidenuded areas, hence it 

 is more abundant where it is found in moist, clay soil in fallow fields. It is 

 found in wet places in woodland, ditches, and marshes, along streams, and 

 about lakes. Sometimes the base is immersed in water when it may be 

 mistaken for Nasturtium officinale or vice versa. The species may be 

 separated easily by the size of the flowers. The calyx of this species 

 is about 2 mm long and petals about 3 mm long while those of Nasturtium 

 are about 3 mm and 4 mm long respectively. 



This species is very difficult to separate from the next. Most specimens 

 are easily distinguishable by the habitat but we have specimens from 

 moist, clay soil of fallow fields (the habitat of this species) that, so far 

 as I can determine, belong to the next species. Contrary to my prejudice, 

 I am compelled to recognize two habitats for the next species. 



Lab., to Minn., and Mont, to B. C, southw. to Fla., Kans. and Calif. 



5. Cardamine parviflora L. var. arenicola (Britt.) O. E. Schulz. (Rho- 

 dora 29: 192. 1927.) (Cardamine parviflora L. and Cardamine arenicola 

 Britt.) Small-flower Bittercress. Map 1026. This species is prob- 

 ably found in all parts of the state except in the rich, neutral soil of the 

 central part. It is rare to infrequent and is usually found in dry soil in 

 bare spots in woodland under black and white oak or in a habitat simulat- 

 ing this one. On these bare spots the plants may be only 2-3 inches high 

 but on or near the border where the leaf mold and vegetation about such 

 places begin the largest plants will be found. The plant is so delicate that 

 it can not push its way through leaf mold or compete with much vegetation. 

 There are, however, plants that must belong to this species that are found 

 in moist, clay soil in fallow fields where they are usually associated with 

 Agrostis hyemalis, Cardamine pennsylvanica, Hordeum pusillum, and 

 Arabis virginica. I am of the opinion that both habitats have slightly 

 acid soil. 



Que. to Ga. and the Mississippi Valley to Oreg. 



