CRUCIFER^ 335 



5. DENTARIA. Toothwokt. 



Low herbs, perennial, found in damp woodland, blooming with the early 

 spring flowers, bearing flowers in corymbs, white, roseate or purplish, 

 larger than the similar flowers of Cardamine: rootstocks long, horizontal, 

 scaly or toothed, aromatic or with cress-like taste: stems erect, unbranched, 

 leafless below, with 2 or 3 palmately divided or compound leaves on petioles, 

 near the middle: fruit a linear silique, flattened, valves not nerved, with 1 

 row of seeds in each cell: seeds not winged. 



D. diphylla, Linn. Crinkle -root. Pepper-root. Stem erect, from a 

 toothed rootstoek: leaves usually 2: leaflets three-parted, wide-ovate, with 

 margins dentate: flowers white. 



D. laciniata, Muhl. Fig. 240. Rootstoek deep, short, tuberous, con- 

 Btricted in several places (necklace-like): stem leaves 3, nearly verticillate, 

 deeply 3-parted into lanceolate, linear or oblong leaflets, which are lobed or 

 toothed, and some 2-cleft: flowers white or pinkish, smaller than preceding. 



6. CABDAMINE. Bitter-cress. 



Very similar to Dentaria, the chief difference being in the stem, which 

 is leafy, and the leaves simple, usually more or less lobed, alternate on stem. 

 Glabrous perennials, growing in wet places and along waterways, from 

 fibrous roots or tubers (not scaly rootstocks), the flowers white or purple in 

 terminal racemes. 



C. rhomboldea, DC. Stem simple, erect, 9-18 in., from a tuber: leaves 

 simple, petioled below, ovate or rhombic-oblong in shape: petals white, 

 small, much longer than calyx. A variety purpurea, not so tall (4-6 in.), 

 with rose-colored flowers, appears even earlier than the type. 



7. NASTTJRTIUM. Water-cre<s. Horseradish. 



Low, mostly aquatic or marsh plants, with pinnate or pinnatifled leaves, 

 (sometimes simple); flowers small, white or yellow, with spreading sepals: 

 stamens 1-6: fruits various, short and broad (siliele) or short-cylindrical: 

 valves convex, nerveless or 1-nerved. 



N. officinale, R. Br. Water-cress. Glabrous, growing in or about water: 

 stems spreading, rooting at the nodes: leaves pinnately lobed, with 3-11 

 lobes, the terminal segment largest: flowers small in racemes, which 

 elongate as the fruits mature: petals white and twice as long as the sepals. 

 A favorite plant for salads. 



N. palustre, DC. Marsh-cress. Annual or biennial, with simple, 

 fibrous roots: stem erect, 1-2 ft., glabrous or slightly pubescent: pinnately 

 lobed leaves, the upper sessile: flowers small, yellow; pods oblong or ovoid, 

 turgid, little if any lunger than the pedicels. Weed in marshy places. 



N. Armor&cia, Fries. Horse-radish. Cultivated, but sometimes escaped 

 into waste grounds: perennial, the roots long and thick: root leaves large, 

 coarse, glabrous, oblong, crenate, rarely pinnatifled, on thick petioles, 

 the stem leaves sessile, lanceolate: flowers small, petals white, longer than 

 calyx. 



