'10 American Midland Naturalist Monograph No. 7 



31. Petals deeply bifid; pods ellipsoid to nearly globose, scarcely 



flattened; seeds several in each locule, winged 26. Berteroa 



31. Petals entire or nearly so; pods strongly flattened. 



32. Pods triangular 32. Capsella 



32. Pods rounded or nearly so. 



33. Plants densely stellate-pubescent 24. Alyssum 



33. Plants with 2-pointed hairs 25. Lobularia 



1. Cakile Mill. — Sea Rocket 

 C. edentula (Bigel.) Hook. Shore of L. Michigan, not common. 

 July-Sept. [C. americana Nutt.] 



2. Raphanus L. — Radish 



1. Pods conspicuously torulose and longitudinally ridged when dry, 

 3-4 mm thick; petals yellowish, spatulate, clawed, veiny, fading 

 whitish or purplish; fields and waste ground; nat. from Eur. 

 June-Aug. Wild Radish R. raphanistrum L. 



1. Pods smooth, not torulose, 5-9 mm thick; petals purple, less com- 

 monly white, 1.5-2 cm long, conspicuously veined; fields and 



waste ground; escaped from cult. May-Sept. Radish 



R. sativus L. 



3. Eruca Adans. — Rocket Salad 



E. sativa Mill. Nat. from Eur. ; Peoria Co. F. E. McDonald in 

 1907. 



4. Erucastrum (DC.) Presl — Dog Mustard 



E. gallicum (Willd.) O. E. Schulz. Waste ground; adv. from Eur. 

 June-Oct. 



5. Brassica L. 

 1. Leaves not clasping the stem. 



2. Pods hispid, 3 cm long, with a flattened beak half the length of 

 the pod; fields and waste places; nat. from Eur. Apr.-Aug. 

 White Mustard [B. alba sensu auth., non Gilib.; Sinapis alba 



L.J B. hirta Moench 



2. Pods glabrous. 



3. Pods ascending at maturity, 3-5 cm long, 2-3 mm thick, the 



beak 4-8 mm long; pedicels ascending, 6-10 mm long. 



4. Beak of the mature pod flattened, nearly as wide as the 



body, usually containing one seed in the basal part; 



pedicels stout, 4-6 mm long; fields and waste places; nat. 



from Eur. Mav-Sept. Field Mustard [B. arvensis 



Rabenh., non L.]' B. kabcr (DC.) L. C. Wheeler 



4. Beak of the mature pod terete, seedless ; pedicels slender, 

 7-10 mm long; fields and waste places; nat. from Eur- 

 asia. July-Sept. Indian Mustard B. juncea (L.) Cosson 



3. Pods erect, 1-1.5 cm long, 1-1.5 mm thick; beak terete, 1.5-2 

 mm long; pedicels erect, 3-5 mm long; fields and waste 



places; nat. from Eur. Apr.-Sept. Black Mustard 



B. nigra (L.) Koch 



