18 SPRING FLORA OF MANHATTAN. 



1. Capsule compressed parallel to partition. 



Linear, elongated. 



Leaves dissected, grouped near middle of stem Dent-aria 



Leaves undivided; stem leafy Arabis 



Oblong; low plants Drdba 



2. Capsule terete or 4-angled. 



Short, valves convex, nerveless Boripa 



Valves convex or keeled, nerved; flowers very small, yellowish, 



Sisymbrium 

 Flowers larger; capsule beaked beyond the valves Brassica 



3. Capsule short, flattened contrary to partition. 



Obcordate » Bursa 



Orbicular; stamens only 2; often apetalous Lepidium 



RORIPA, Scop. 



B. Armoracia, (L ) The common horse-radish with white flowers 

 and large leaves. Sometimes spontaneous near gardens. 



It Nasturtium, (L.)Rusby. Flowers white. Capsules linear. Leaves 

 pinnate. Wet places, rare. 



B. sessiliflora, (Nutt.) Flowers yellowish, very small. Capsules 

 about 1 cm. long, nearly sessile. Leaves lyrate. Wet places, common. 



B. sinuata, (Nutt.) Flowers yellow, 1 cm. long. Capsules about 1 

 cm. long, on slender pedicels. Common. 



ARABIS, L. 

 A. Canadensis, L. Stem i-1 m. high, leafy. Leaves oblong-lanceolate, 

 not clasping, somewhat toothed. Flowers whitish. Capsules curved, 

 elongated, very flat, pendulous. Woods, frequent. 



A. hirsuta, (L.) Scop. Leaves clasping by a sagittate base. Flowers 

 greenish. Capsules upright, straight. Rocky woods, common. 



DENTARIA, L. 

 D. lacininta, Muhl. Flowers white or pink; leaves 3-parted. Woods, 

 rare. 



DRABA, L. 

 D. Caroliniana, Walt Plants a few cm. high. Flowers white. 

 Leaves obovate, entire, hirsute. Capsules smooth, or in var. micrantlia, 

 (Nutt.) Gray, minutely hairy. Waste places, common. 

 SISYMBRIUM, L 

 S officinale, (L.) Scop. Leaves 1-pinnatifld. Capsules nearly sessile, 

 closely appressed to stem. A common weed. 



S. pinnatum, (Walt.) Greene. Leaves 2-pinnatifid. Capsules spread- 

 ing on horizontal pedicels. Open ground, common. 



BRASSICA, L. 



B. nigra, (L.) Koch. Flowers bright yellow, rather large. Leaves 

 with a large terminal lobe and a few small lateral ones. Stem somewhat 

 hairy. Capsules 4-angled. Waste places, frequent. 



B. Sinapistrum, Boiss. As in B nigra, but stem smooth and 

 glaucous and leaves more or less sagittate-clasping. Capsules terete and 

 knotty. Waste places, frequent. 



