White to Green and Brown Flowers 133 



WHITE WHITLOW GRASS 



Draha incana. Mustard Family 



Stems: hoary, pubescent. Leaves: oblong-lanceolate, nearly entire. 

 Flowers: petals notched; style minute. Fruit: pods acute, twisted when 

 ripe, on short erect pedicels. 



A plant partaking of the appearance of a weed, and 

 closely resembling- a white mustard. It has lance-shaped, 

 toothed leaves, and the petals are notched at the apex. 



Draba lonchocarpa, or Long-podded Whitlow Grass, may 

 be recognized by its long smooth pods, which are very nar- 

 row, and more or less twisted. It is a hairy plant and grows 

 on rock ledges at great altitudes. 



Draba prccalia, or Spring Whitlow Grass, is a common 

 species which grows abundantly between four and six thou- 

 sand feet. 



PENNY CRESS 



Thlaspi arvense. Mustard Family 



Stems: erect, glabrous. Leaves: petioled, oblanceolate, dentate; 

 stem-leaves oblong. Flowers: white, pedicels spreading or curved up- 

 ward. Fruit: pods nearly orbicular when ripe, broad, very flat, notched 

 at the apex, in long racemes ; seeds rugose. Not indigenous. 



Penny Cress very nearly resembles Shepherd's Purse, and 

 the easiest way to distinguish between the two plants is to 

 note that while the seed-pods of the latter are triangular in 

 shape, those of the Penny Cress are nearly round, both being 

 notched at the top. Then, also, the leaves differ : those of 

 the Shepherd's Purse are deeply cut, and those of the Penny 

 Cress are only slightly toothed. This is an introduced 

 plant. 



