MUSTARD FAMILY 283 
Flowers yellow 
Pods elongated. 
Slender, not constricted between seeds . - S. sylvestris 
About as long as the pedicel and constricted between seeds - R. palustris 
Pods globose or ovoid «<<: « «= « 2 ; le ites ispida 
3. R. armoracia, (L.) Rusby. Russpy’s Water Cress.  Branch- 
ing plant, floating or spreading and rooting at branches in brooks and 
ditches. Leaves generally of 3 leaflets, but these may be in greater 
number, from 5 to 9. Terminal leaflet Jargest. Brooks and streams. 
Naturalized. April-Nov. 
2. R. americana, (Gray) Britton. Aquatic, upper leaves oblong, 
not. divided, immersed leaves pinnately divided and finely dissected. 
Pods ovoid. 
1. R. Nasturtium,(L.) Hitcheock. (Fig. 8, pl. 56.) Horse Rapisu. 
Basal leaves feather-formed, oblong, very large, those of stem lance-form. 
Roots long and large. Escaped from gardens. Moist grounds, along 
streams, ete. 
4. R. sylvestris, (L.) Bess. CREEPING YELLOW WATER CRESS. 
Stems smooth, angular, from creeping root-stocks. Leaves variable, 3 to 
5 in. long and deeply divided pinnately, the sinuses extending to mid- 
vein. Flowers yellow, pod 3 in. long or less. Moist grounds, Nat- 
uralized. 
5. R. palustris, (L.) Bess. (Fig. 3, pl. 55.) Marsa WATER CREss. 
Hairy plant 1 to 2 ft. high, with leaves deeply cut pinnately, the sinuses 
less completely dividing into leaflets than No. 4. Terminal leaflet larger, 
sometimes 6 in. long, Flowers 1/8 in. in diameter, yellow. Pods linear- 
oblong, turgid, 2 to 6 times as long as thick. Wet places. Naturalized. 
May-Aug. 
6. R. hispida, (Desv.) Britton. (Fig. 8, pl. 54.) Hispip YELLow 
Cress. Resembling No. 5, but generally stouter, 1 to 4 ft. high. All 
parts covered with spreading hairs, pods ovoid or round. Naturalized. 
Waste places. May-June. 
Flowers white or purple 
19. DENTARIA, L. 
Herbs with 3- or 5-divided leaves; slender and rather long and flat seed 
pod. Seeds in a single row in each valve, the seed stalks alternating on 
opposite sides of the valves. Stems naked below, bearing above 2- or 
3-parted or rarely 5-parted leaves and a cluster of whita or purple 
flowers. Rootstocks rather fleshy and knotted, mostly horizontal. 
1. D. laciniata, Muhl. (Fig. 3, pl. 56.) CUT-LEAVED TooTHWworRT, 
PEPPER Root. Plant 8 to 15 in. high, root-stock markedly jointed. Stem 
branching into 3 leaf-stalks and the flower stem. Leaflets each carrying 
a leaf 2 to 5 in. broad, divided into 3 leaflets, these sometimes rather 
deeply divided; teeth coarse. Other leaves start on long leaf-stalks di- 
rectly from the root. Flowers nimerous, white or rose color. Woods. 
April-June. 
2. D. diphylla, Michx. (Fig. 4, pl. 56.) Two-LeAvep Tootuwort. 
Plant about as high as No. 1; stem bearing two leaf-stalks, each 3-parted, 
