32 
Fifteenth class. 
— Silicules 2-celled, with 2—several seeds, not pendant 
Alyssum. 52. 
31. Silicules indented above and below (like spectacles), 
2-celled, 2-seeded.Biscutella. 66. 
— Silicules oblong-cuneiform, 1-celled, l-seeded Isatis. 73. 
32 (1). Siliquas indehisc., or separating transversely by ar¬ 
ticles. (Ls lyrate).. . 33 
— Siliquas opening by 2 valves .... 34 
33. Siliquas contracted between the seeds like a string of 
beads, and separating at last into l-seeded articles 
Raphanistrum. 80. 
— Siliquas inflated, spongy at maturity, very slightly or 
not at all contracted between the seeds and not separ¬ 
ating at maturity. Radish . . . Raphanus. 81. 
34. FIs yellow or yellowish ..... 35 
— FIs white, lilac or red ...... 4:5 
35. Seeds 1-seriate in each cell ..... 36 
— Seeds 2-seriate (sometimes rather indistinctly) in each 
cell ......... 44 
36. Stig. 2*lobed, with reflexed lobes. Ls entire 
Cheiranthus. 31. 
— Stig. obtuse or indented ..... 37 
37. Valves 1-nerved (on the side of the strong dorsal nerve 
there are often reticulated veins resembling indistinct 
lateral nerves) ..... . . 38 
— Valves 3—5-nerved (nerves gen. strong and straight) 43 
38. Ls all undiv., only dentate or sinuate-dentate . 39 
— Ls all, or at least the lower ones, lyrate-pinnatipartite, 
or simply 2—3-pinnatisect ..... 40 
39. Siliquas 4-cornered. Seeds rather long. Pis with, gen. 
branched, hairs ..... Erysimum. 45. 
— Siliquas cylindric. Seeds globular. Pis glabr. or with 
simple hairs ...... Brassica. 46. 
40. Seeds globular ..... Brassica. 46. 
— Seeds ovoid or elliptic . . . . . .40a 
40a. Ls 2—3-pinnatisect, with linear segments 
Sisymbrium. 39. 
— Ls with other characteristics .... 41 
41. Racemes arranged in a corymb. Siliquas not more than 
15 mm in length. Alpine pis . . Hugueninia. 41. 
— Racemes solitary. Siliquas more than 15 mm long 42 
42. Pis glabrous.Barbarea. 33. 
— Pis more or less hairy . , . Erucastrum. 48. 
43 (37). Siliquas terminating in a beak 10—20 mm long. 
Seeds globular ..... Sinapis. 47. 
— Siliquas without, or with a very short, beak. Seeds 
ovoid or elongated .... Sisymbrium. 39. 
44(35). Siliquas compressed. Valves 1-nerved Diplotaxis. 49. 
