152 CRUCIFER.E. 



cence, with simple or 2 - 3-pinnately dissected leaves, and 

 white or yellow flowers. Racemes elongated in fruit, ebrac- 

 teate, or rarely with the flowers subtended with leaf-like 

 bracts. 



Etymology. 'Sio-ifi^piov, an ancient name for some plants of this family. 



Geographical Distribution, &c. A pretty large genus, widely dis- 

 tributed over the world, comprising some heterogeneous forms. S. offici- 

 nale, the Hedge-Mustard, an introduced plant with us, represents a section 

 which may perhaps be taken as the type of the genus. Our figure illus- 

 trates only the section Irio, D C. 



PLATE 64. Sisymbrium canescens, Nutt. ; — a small plant; natural 

 size. (Texas, Lindheimer.) 



1 . A flower, enlarged. 



2. A sepal, and 3, a petal, more enlarged. 



4. Stamens and pistil. 



5. A ripe silique, enlarged. 



6. The same, divided transversely near the base. 



7. Portion of the replum, with seeds, more magnified. 



8. A magnified seed, divided, showing the incumbent cotyledons. 



9. Hairs from the foliage, magnified. 



