20b. Leaves broad, irregularly pinnatifid especially below the middle, with a large terminal segment --21. 21a. Beak of pod 3-4 mm. long =Black Mustard, Brassica nigra.= 21b. Beak of pod 5 mm. long or more =Indian Mustard, Brassica juncea.= 22a. Leaves dentate or lobed =Charlock, Brassica arvensis.= 22b. Leaves deeply pinnatifid --23. 23a. Pod dehiscent when ripe by two valves, tipped with a flat or angled beak =White Mustard, Brassica alba.= 23b. Pod indehiscent, with spongy cross-partitions between the seeds, tipped with a conical beak =Wild Radish, Raphanus raphanistrum.= 24a. Terminal segment of the principal leaves much larger than the lateral segments; flowers in spring and summer --25. 24b. Terminal segment of the principal leaves equaling or smaller than the lateral ones (5-10 dm. high; pods very long and slender; flowers in summer) =Sisymbrium, Sisymbrium altissimum.= 25a. Flowers about 3 mm. wide; pods erect and closely appressed to the stem (3-9 dm. high; weed blooming in summer) (Hedge Mustard) --26. 25b. Flowers about 7 mm. wide; pods spreading or ascending (3-6 dm. high; flowers in spring) (Winter Cress) --27. 26a. Pods pubescent =Hedge Mustard, Sisymbrium officinale.= 26b. Pods glabrous =Hedge Mustard, Sisymbrium officinale var. leiocarpum.= 27a. Lateral leaf-segments 5-8 pairs on the principal leaves =Winter Cress, Barbarea verna.= 27b. Lateral leaf-segments 1-4 pairs on the principal leaves --28. 28a. Flowers bright yellow, in racemes; pods spreading or ascending =Winter Cress, Barbarea vulgaris.= 28b. Flowers pale yellow, in corymb-like clusters; pods erect and somewhat appressed =Winter Cress, Barbarea stricta.= 29a. Principal stem-leaves compound or deeply lobed (the uppermost or bracteal leaves may be simple) --30. 29b. Principal stem-leaves entire, dentate, serrate, or sometimes shallowly lobed or none (the basal leaves, at the surface of the ground, may be deeply lobed or compound) --42. 30a. Leaves ternately divided or compound (2-5 dm. high; flowers in spring) (Toothwort) --31. 30b. Leaves pinnately divided or compound --33. 31a. Leaf-segments lanceolate or narrowly oblong =Toothwort, Dentaria laciniata.= 31b. Leaf-segments ovate or ovate-oblong --32. 32a. Stem-leaves 2, opposite or nearly opposite =Toothwort, Dentaria diphylla.= 32b. Stem-leaves 2-5, alternate =Toothwort, Dentaria maxima.= 33a. Plants growing in water, or in mud near water (spring and summer) --34. 33b. Plants of dry or moist soil --35.