FLORA OP PHILADELPHIA. 



Seeds flat, wingless, or winged. 



Siliques 4-angled, the valves keeled; flowers yellow. 



11. Barbarea. 

 Siliques flat or flattish. 



Valves of the silique nerveless. 



Stems leafy below or throughout. 13. Cardamine. 

 Stems leafless below, 2-4 leaved above. 



14. Dentaria. 

 Valves of the silique l-nerved or veiny, not elastically de- 

 hiscent. 24. Arabis. 

 b. Silique produced into a beak beyond the valves. 

 Beak conic, very short in No. 8. 



Silique terete ; seeds in 1 row. 8. Brassica. 



Silique flat; seeds in 2 rows. 9. Diplotaxis. 



Beak flat, sword-shaped. 7. Siriapis. 



U. Silique elliptic or oblong, very flat, 2-3 times as long as broad, cleai'ly 

 stipitate. 15. Lunaria. 



ffPod an orbicular globose or oblong silicle, or but little more than twice 

 as long as wide. 



a. Silicle globose, or flattened parallel with the septum. 



Silicle globose, or terete-oblong, little or not at all compressed. 

 Seeds minute, round, not flattened, in 2 rows in each celL 



12. Boripa. 

 Seeds flat; silicle inflated; plants stellate-pubescent. 



16. Lesquerella. 

 Silicle compressed or flat, many-seeded. 21. Draba, 



Silicle compressed or flat, many-seeded. 



Flowers yellow. 26. Alyssum. 



Flowers white. 27. Koniga. 



Silicle pear-shaped or obovoid, many-seeded. 



18. Camelina, 



b. Silicle flattened at right angles to the narrow septum. 



Seeds several in each cell of the silicle. 



Silicle triangular, obcuneate. 17. Bursa. 



Silicle oblong or orbicular, winged all around. 



3. Thlaspi. 

 Seeds solitary in each cell, compressed. 1. Lepidium. 



**Pod indehiscent, short or elongated. 



Pod broader than long, more or less didymous. 2. Corovopiis. 



Pod globose, reticulated. 19. Neslia. 



Pod elongated. 



Pod of 2 joints, separating at maturity. 



Lower joint of pod seedless or 2-4-seeded; cotyledons condupli- 



cate. 20. Rapistrum. 



Lower joint of pod 1-seeded; cotvledons accumbent. 



6. CaJcile. 

 Pod constricted between the seeds, not jointed, beaked. 



10. Raphanus. 



1. LEPIDIUM L. Peppergrass. 



Stem-leaves clasping by an auriculate base. 



Pods broadly ovate, winged. 1. L. campestre. 



Pods wingless, broader than long. 2. L. Draba. 



Stem-leaves petioled or sessile, not clasping. 



Pods and seeds entirely wingless ; petals none. 3. L. ruderale. 



Pods slightly winged above, orbicular or oval, about 2 mm. broad; 

 petals present or none. 

 Cotyledons accumbent ; petals generally present. 4. L. Virginicum, 

 Cotyledons incumbent; petals minute or wanting. 



5. 2/. apetalum. 



