140 CRUCIFER^E. 



Etymology and Geographical Distribution. Dedicated to Dr. M. C. 

 Leavenworth, the discoverer of one species, if, indeed, L. aurea is distinct 

 from L. Michauxii, the Cardamine uniflora, Michx. These little plants 

 grow on wet rocks, &c, in Eastern Kentucky, Tennessee, and Alabama : 

 also in Arkansas. . 



Note. The embryo in this genus exhibits a remarkable " arrest of de- 

 velopment," of which there is no other example in the family. In the fully 

 ripe seeds, the cotyledons remain straight, in the same line with the radicle, 

 just as in the half-grown embryos of other Cruciferae, or else (in L. Mi- 

 chauxii, Torr.) the cotyledons are slightly inclined to one side, so as to 

 manifest barely a disposition to become accumbent. 



PLATE 57. Leavenworthia aurea, Torr.; — specimen from Tennes- 

 see, Mr. Buckley; of the natural size. 



1 . A flower, enlarged. 



2. A sepal, more enlarged ; inside view. 



3. A petal, equally magnified. 



4. Stamens and pistil, magnified. 



5. An enlarged silique, the valves removed, showing the seeds, &c. 



(From an Arkansan specimen, gathered by Dr. Leavenworth.) 



6. Tissue of the partition, highly magnified. 



7. Magnified seed, divided transversely through the cotyledons. 



8. Embryo, detached. 



