BRASSICACEAE. 137 



Petals cuneate ; blades 2-cleft : pods long-pedicelled, elliptic to oblong-elliptic. 



1. D. vcrna. 

 Petals not cuneate ; blades entire : pods short-pedicelled, linear. 2. D. caroUniana. 



1. D. verna L. Plants 2-16 cm. tall, acaulescent: leaf -blades spatulate to 

 narrowly oblong, 5-15 mm. long, entire, or toothed near the apex, sparingly 

 pubescent: scapes glabrous: sepals becoming 1.5-2 mm. long: petals cuneate, 

 nearly twice as long as the sepals: pods elliptic to oblong-elliptic or rarely 

 oval, 4-9 mm. long. — Common, on dry banks and in fields. Nat. of Eu. — 

 Whitlow-grass. 



2. D. caroliniana Walt. Plants 4-10 cm. tall, often short-stemmed: leaf- 

 blades obovate, spatulate, oblong, or suborbicular, 5-15 mm. long, entire or 

 shallowly few-toothed, closely pubescent: scapes pubescent, at least below: 

 sepals becoming 2-2.5 mm. long, glabrous: petals 3-4 mm. long, with cuneate 

 or oval blades: ovary glabrous: pods linear, 7-18 mm. long. — M. Eare, on 

 rocks near Lancaster. — Limestones. 



21. CAEDAMINE [Tourn.] L. Annual or perennial herbs with erect or 

 creeping stems. Leaves alternate : blades entire to pinnately dissected. Sepals 

 4, much shorter than the petals. Petals 4, white, pink, or purple. Style very 

 short. Pod elongate. — Spr. — Bitter-cress. 



Leaf-blades entire or undulate. 1- C. bulbosa. 



Leaf-blades, at least those of cauline leaves, pinnately divided. 



Corolla 3 mm. wide or narrower. 2. C. parvifloi-a. 



Corolla 4 mm. wide or broader. 



Sepals about 1 mm. long : segments of the cauline 



leaves linear. 3. 0. arenicola. 



Sepals about 2 mm. long : segments of the cauline 



leaves oblong or broader. 4. C. pennsylvanica. 



1. C. bulbosa (Schreb.) B. S. P. Plants 1-5 dm. tall, with tuber-like bases: 

 eauline-leaves 3-8 cm. long; blades oval, oblong, ovate, or lanceolate: sepals 

 becoming 3-3.5 mm. long: petals broadly cuneate, 7-12 mm. long: pods 

 mostly 2-2.5 cm. long. — Common, in swamps and low woods. — Spring-cress. 



2. C. parviflora L. Plants with slender stems 0.5-3 dm. tall: cauline leaves 

 1.5-6 cm. long; blades pinnately divided, the several lateral segments narrow, 

 but broadened upward: sepals becoming 1-1.5 mm. long: petals slightly longer 

 than the sepals: pods 1.5-2.5 cm. long. — S. Frequent, on dry banks along 

 the Susquehanna Eiver. — Schists. 



3. C. arenicola Britton. Plants 1-3 dm. tall: cauline leaves 1-4 cm. long; 

 blades pinnately divided, the lateral segments linear or linear-oblong, mainly 

 entire: sepals becoming about 1 mm. long: petals about twice as long as the 

 sepals, mostly cuneate: pods linear, about 2 cm. long. — S. Eare, in spring- 

 runs and moist sandy soil. — Schists. 



4. C. pennsylvanica Muhl. Plants 2-10 dm. tall, glabrous or nearly so: 

 cauline leaves 4-8 cm. long; blades pinnately divided, the lateral segments 

 very broad or narrow, undulate, toothed, or lobed: sepals becoming about 2 

 mm. long: petals somewhat longer than the sepals, mostly spatulate: pods 

 linear-filiform, 2-2.5 mm. long. — Common, in wet places and meadows. 



22. DENTAKIA [Tourn.] L. Perennial scapose herbs with horizontal 

 rootstocks. Leaves basal: blades palmately cleft or divided. Scapes simple, 

 each bearing 2 or 3 bracts with blades similar to the basal leaves. Sepals 4, 

 much shorter than the petals. Petals 4, white or purple, relatively large. 

 Stamens 6; anthers oblong to lanceolate. Style slender. Pod elongate. 



1. D. laciniata Muhl. Eootstock jointed: scapes 1-3.5 dm. tall: bracts 3; 

 segments with linear-lanceolate or oblong coarsely serrate or incised blades: 



