THE MUSTARD FAMILY. 171 



XXIII. THE MUSTARD FAMILY. CRUCIFER^. 



MATERIAL REQUIRED. 



Entire plants of Shepherd's-purse, Capsella Bursa-pastoris, Mcench, 

 with both flowers and fruit. 



Specimens of any of the following species that can be obtained : 

 Spring Cress, Cardamine rhomboidea, DC. ; Pepper-root, Dentaria 

 diphylla, L. ; Water Cress, Nasturtium officinale, 11. Br. ; Sweet 

 Alyssum, Alyssum maritimum. Lam.; Rocket, Hesperis matronalis, 

 L. ; Peppergrass, Lepidium Virginicum, L. ; Hedge Mustard, Sisym- 

 brium officinale, Scop. ; Wild Mustard, Brassica Sinapistrum, Boiss. 



SHEFHERD'S-FURSE. Capsella Bursa-pastoris, Moench. 

 Distribution. 



Record your own observations as to the occurrence arid 

 habits of this plant. Does it manifest a preference for 

 any particular soil or locality ? 



General Characters. 



Write an accurate description of the root, stem, leaves, 

 and inflorescence. 



Flower and Fruit. 



I. Study the plan of the flower, noting the number and 

 arrangement of sepals, petals, and essential organs. Show 

 the application of the word "cruciform" as used to 

 describe the corolla. Are the stamens all alike ? 



II. Examine the structure of the ovary. Compare it as 

 it appears in the flower, with partially and fully developed 



