CRUCIFER.E. (MUSTARD FAMILY.) 23 



ORDER 11. CRUCIFERyE. (MUSTARD FAMILY.) 



Herbs with pungent watery juice, alternate exstipulate leaves, and 

 regular hvpogenous racemose or corymbose bractless flowers. Fruit 

 a silique or silicle. Sepals 4, deciduous. Petals 4, regular, placed 

 opposite each other in pairs, their spreading limbs forming a cross. 

 Stamens G (rarely fewer), two of them shorter. Capsule 2-celled by 

 a membranaceous partition which unites the two marginal placentas, 

 from which the two valves separate at maturity, or indehiscent and 

 nut-like, or separating into 1-seeded joints. Seeds campylotropous, 

 without albumen, filled with the large embryo, which is curved en- 

 folded in various ways, or straight only in Leavenworthia. (The 

 genera are distinguished chiefly by the fruit and seed ; the flowers 

 being nearly similar throughout the order.) 



Synopsis. 

 I. SILIQUOS^E. Fruit a silique, few -many-seeded. 



* Cotyledons flattened, parallel with the partition, one edge applied to the ascending 



radicle (decumbent). 

 -i Valves of the fruit nerveless. 



1. NASTURTIUM. Silique short, nearly terete. Seeds in two rows in each cell. 



2. CARDAMINE. Silique linear, compressed. Seeds wingless, in a single row. 



3. DENTARIA. Silique lanceolate, compressed. Seeds wingless, in a single row. 



4. LEAVENWORTHIA. Silique oblong. Seeds winged. Embryo straight. 



M H Valves of the fruit 1-nerved. 



5. ARABIS. Silique linear, elongated : valves flattened. 



6. IODANTHUS. Silique nearly terete : valves convex. Flowers purple. 



7. BARBAREA. Silique terete or 4-sided. Seed wingless. Flowers yellow. 



* * Cotyledons flat, with one edge turned toward the partition, and the back of one of them 



applied to the ascending radicle (incumbent). 



8. SISYMBRIUM. Silique sessile, nearly terete. 



9. WAREA. Silique stalked, compressed. Petals on long claws. 



10. ERYSIMUM. Silique 4-angled, valves keeled. Leaves entire. Flowers yellow. 



11. HESPERIS. Silique nearly terete. Seeds triangular. Leaves toothed or serrate. 



12. SINAPIS. Silique beaked. Seeds globular. Cotyledons folded. 



II. SILICULOS^E. Fruit a silicle. 



* Silicle compressed parallel with the broad partition, or globular. 

 H Cotyledons accumbent. 



13. DRABA. Silicle oval or oblong, many-seeded : valves 1-3 nerved. 



14. LESQUERELLA. Silicle orbicular, few-seeded : valves nerveless : flowers yellow. 



15. ALYSSUM. Silicle orbicular, 2 - 4-seeded : flowers white. 



-t -i Cotyledons incumbent. 



16. CAMELINA. Silicle obovoid : valves 1-nerved. 



* * Silicle compressed contrary to the narrow partition. Cotyledons incumbent, rarelj 



accumbent. 



17. SENEBIERA. Valves of the silicle globular, rugose : seeds solitary. 



18. LEPIDIUM. Valves of the silicle boat-shaped : seeds solitary. 



19. CAPSELLA. Valves of the silicle boat-shaped : seeds numerous. 



III. LOMENTACE^E. Fruit separating transversely into joints. 



20. CAKTL 1 ^. F--i*. 'JMointfld. 



