June, 1917] The BrassicacecB of Ohio 309 



II. Pod usually clongalcd-linear, more than twice as long as wide (a silique). 



A. Pod not transversely 2-jointcd. 



1. Cotyledons accumbent or incumbent; pod not beaked, but often 

 tipped with the style; seeds usually in one row in each cavity. 



a. Cotyledons incumbent. 



NORTK.4-;. 



Alliaria, vSophia, Chcirinia, Erysimum, Xorta, Conringia, 

 Hesperis, Arabidopsis. 



b. Cotyledons accumbent. 

 Arabide.e. 



Barbarea, lodanthus, Arabis, Cardamine, Dentaria. 



2. Cotyledons conduplicate; pod beaked. 



BRASSICEiE. 



Sinapsis, Brassica, Diplotaxis. Raphanus. 



B. Pod transversely 2-iointed, fleshy, indehiscent; cotyledons accumbent. 



C.A.KILE/E. 



Cakile. 



Key to the Genera of the Brassicace.e of Ohio Based on the Flower and 

 Other Char.\cteristics Present at Anthesis. 



1. Flowers white. 2. 



1. Flowers yellow. 19. 



1. Flowers purple. 32. 



2. Leaves simple, not lobed. 3. 



2. Leaves deeply lobed or pinnatifid. 12. 



3. Stems scapose; basal leaves in a rosette. Draba. 



3. Stems leafy. 4. 



4. Leaves entire. 5. 



4. Leaves dentate, crenate or wavy. G. 



5. Petals bifid; plant hoary-pubescent. Berteroa. 



5. Petals entire; plant appressed-pubescent; flowers fragrant. Koniga. 



6. Basal and stem-leaves the same. 7. 



6. Basal and stem-leaves different. 8. 



7. Leaves broadly cordate, dentate; petals clawed. Alliaria. 



7. Leaves orbicular, wavy; stems decumbent, stoloniferous. Cardamine. 



8. Stem-leaves sessile; petals twice the length of the sepals. 9. 



8. Stem-leaves clasping. 10. 



9. Basal leaves oblanceolate, rosulate; stem-leaves lanceolate; pubescent with 



forked hairs. Arabidopsis. 

 9. Basal leaves obovate; stem-leaves lanceolate, narrowed at each end; pods 



scythe-shaped. Arabis. 

 10. Basal leaves oblanceolate, early deciduous; stem-leaves lanceolate; pods 

 broadl}' winged. Thlaspi. 



10. Basal leaves obovate or spatulate, dentate; flowers less than one-third inch 



broad. 11. 



11. Racemes dense; silicles orbicular. Lepidium. 



11. Racemes loose; siliques flat, linear. Arabis. 



12. Basal and stem-leaves the same. 13. 



12. Basal and stem-leaves different. 15. 



13. Leaves deeply lobed or pinnatifid. 14. 



13. Leaves palmately 3-lobed; stems leafless below; flowers corymbose. Dentaria. 



14. Stems glabrous, aquatic, rooting at the nodes; end lobe of the leaf large. 



Sisymbrium. 



14. Stems .spreading; plants fetid; pods did^^mous. Carara. 



15. Lower leaves pinnatifid; upper leaves dentate or entire. IG. 



15. Lower leaves pinnatifid; upper leaves smaller and narrower. 18. 



16. Lower leaves immersed, dissected; upper leaves lanceolate. Neobeckia. 



16. Basal leaves large, rough but glabrous; root thick, pungent; pods seldom 



formed. Armoracia. 

 16. Ba.sal leaves in a rosette or rosulate. 17. 



