498 Cruciferae Cardamine 



2. Cardamine Douglassii (Torr.) Britt. (Cardamine bulbosa var. pur- 

 purea (Torr.) BSP.) Northern Bittercress. Map 1023. Rare to in- 

 frequent in all parts of the state but locally frequent. This is strictly a 

 woodland plant and is never found in the open like the preceding one, 

 although it may persist for some time in clearings. It grows in a slightly 

 drier habitat and usually has its base covered with leaf mold, and although 

 Cardamine bulbosa sometimes may have its base in leaf mold it is more 

 often found in muddy places and is most abundant in inundated woodland 

 where the fallen leaves have been floated away. 



Some authors prefer to call this species a variety of the preceding one 

 and technically this decision seems justifiable because no character except 

 color of flower will separate them and intergrading forms are found. Far- 

 well (Amer. Midland Nat. 9: 261. 1925.) described an albino form of this 

 species and other authors agree with him. It is well known that plants 

 with purplish flowers have albino forms and these are known to occur 

 in some species of the Cruciferae. It is with a considerable degree 

 of uncertainty, that albino and fruiting specimens of this species are 

 separated from the preceding species unless a habitat description ac- 

 companies the specimen. I think, however, the species are distinct for 

 the following reasons. (1) This species flowers 10-15 days earlier. (2) 

 The habitat is much drier and I believe that the soil is slightly more 

 alkaline. The preceding species is generally associated with white elm, 

 swamp white, bur, and pin oaks, and sweet gum while this species is gen- 

 erally restricted to a zone slightly drier. The plant blooms in early spring 

 when excessive rains may occur and its habitat may appear much wetter 

 than it normally is so that wetness of soil is no criterion but the associated 

 woody and herbaceous plants are. This species is usually found associated 

 with beech and sugar maple, basswood, red oak, white ash, and others. 

 (3) The plant, in a large series, is smaller in all of its parts; never (in all 

 the specimens at hand) branched while Cardamine bulbosa is frequently 

 more or less branched; cauline leaves generally 3-5 in contrast with the 

 other species with 4-8 leaves ; basal leaves are often more orbicular, smaller 

 and thinner than in the preceding which, on the whole, has larger and 

 more often elliptic-ovate and thicker leaves. I have studied carefully the 

 length of the pods and the length of their beaks and they are too variable 

 to be of taxonomic value. The seed of a long series of this species, how- 

 ever, are smaller. 



Conn, to s. Ont. and Wis., southw. to Md. and Ky. 



3. Cardamine pratensis L. var. palustris Wimm. & Grab. (Fernald in 

 Rhodora 22 : 14. 1920.) (Cardamine pratensis L.) Cuckooflower. Map 



1024. This species inhabits tamarack bogs and marshes in a few of our 

 northern counties. I am not certain of its abundance but I think it is 

 rather rare and local. 



Quebec to Mack., southw. to Newf., Conn., N. J., Ind., Minn., and B. C. ; 

 also in Eurasia. 



4. Cardamine pennsylvanica Muhl. Pennsylvania Bittercress. Map 



1025. Infrequent to frequent throughout the state in wet or moist soils. 



