CRUCIFER&. 259 



one pistil). All the parts of the flower are separate from each 

 other, and make up successive whorls, the pistils terminating 

 the series. When the seeds are ripe the fruit is formed, and 

 may be in the form of a pod, or achene, or in the form of a 

 berry, as in the baneberry (actaea). 



ORDER RHCEADIN^E. 



418. Lesson VIII. The mustard family (cruciferae). This 

 is well represented by the toothwort (dentaria), which we 

 studied in a former chapter. (If the toothwort has been 

 studied, the shepherd 's-purse may be omitted.) 



Exercise 72. 



419. The Shepherd's purse (Capsella bursa-pastoris). If it is desired to 

 study a species besides the toothwort the shepherd' s-purse will answer. It 

 is a common and widely distributed species, found in waste places and in 

 fields. 



The entire plant. Note and describe the habit and character of the plant, 

 i.e., the size, character of branching, character of the root, position and ar- 

 rangement of the leaves. Compare the "radicle" (lower) leaves with the 

 " cauline " (stem) leaves as to form, and insertion. The radicle leaves are 

 more or less deeply lobed or pinnatifid (pinnately cut), while the stem leaves 

 are slender, lanceolate, toothed, and often auricled (with little ears) at the base. 



The inflorescence. What is the kind of inflorescence? Determine the 

 parts of the flower present, as well as the number and arrangement of the 

 members of the flower. What figure do the petals make in the flower, which 

 suggests the name of the family to which the shepherd's purse and the tooth- 

 wort belong ? 



The fruit. What parts of the flower are united in the fruit? Compare the 

 plant with the toothwort. 



Construct the floral diagram of the toothwort or shepherd's purse, or of 

 other cruciferous plant studied. 



Material. Entire plants with flowers and fruit. The plant occurs from 

 early spring to autumn, and can be usually obtained in a fresh condition when 

 wanted. 



The exercise on the violet may be omitted unless it is desired 

 to study it in connection with some field observations, and for 

 the purpose of observing " cleistogamous " flowers, when the 

 outline here given will answer. 



