CABDAMINE. 103 



the two cotyledons. The phrase cotyledons decumbent is 

 applied to seeds so constructed. Compare this with the seed 

 of Oapsella. 



The Name of this plant is Cardamlne diphylla, or the 

 Two-leaved Toothroot. There are other species having 3 

 whorled leaves, and still others with alternate leaves.* 



Classification. Here let the student take note of the 

 affinities of these two genera, Capsella and Cardamine, in 

 the following points. Thus will he learn the characters of a 

 large and important Order, the CRUCIFERS, or Crucifers. f 



Herbs, without stipules. 



Inflorescence centripetal, bractless racemes. 



Flowers cruciform, perfect. 



Stamens didynamous, hypogynous. 



Ovary double. 



Fruit siliques, long or short. 



Seeds exalbuminous, with the embryo bent double. 



The Order of Crucifers is truly natural, and embraces about 

 200 genera and 1600 species, chiefly in the Temperate Zone. More 

 than 100 species are peculiar to this Continent. Among them are 

 nutritious vegetables, as Cabbage, Turnip, Radish. Some are condi- 

 ments in general use ; as Horse-radish, Mustard. The bland Rape- 

 seed oil is expressed from the seeds of the Rape (Brdssica Napus). 

 Woad, a blue dye, is obtained from the root of Isdtis tinctoria.\ In 

 medicine the Crucifers are stimulant and antiscorbutic, but none are 

 poisonous. They all contain a volatile acrid principle abounding in 

 sulphur and nitrogen, which is the cause of the unpleasant odor they 

 emit in decaying. Here too belongs many a favorite garden flower, 

 like Sweet Alyssum, Candytuft, Wall-flower (Cheiranthus), Honesty 

 (Lunwria), and Stock (Matthlola). 



* The Toothroots were first named by Linnaeus, Dentdria (dens, a tooth). The 

 original species were easily distinguished from the genus Cardamine. But other 

 species recently found in California combine the characters of both genera, so as to 

 unite them into one, taking the older name. Some authors, however, still retain the 

 genus Dentaria, and call our plant D. diphylla. This is therefore its synonym. 



t In this connection, let the Mustard plant, Wall-flower, Pepper-grass, Candytuft, 

 &c., be analyzed and registered. 



t This dye is famous in history as having been employed by the Britons in stain- 

 ing their bodies in order to frighten their enemies. 



