292 BOTANY AND PHARMACOGNOSY. 



hawthorn (CratcEgus oxyacantha) contains quercitrin. A bitter 

 principle and tannin are found in Purshia tridentata of the Rocky 

 Mountains. Phlorizin is found in the root bark of a number of 

 species of Pyrus and Primus. 



In the genus Fragaria to which the strawberry belongs, the 

 torus becomes large and fleshy and is the edible part of the fruit. 

 The garden strawberry (F. Chihriisis) has a large, dark-colored 

 fruit, the akenes being sunken in the periphery of the torus. In 

 the wild strawberries the fruit is smaller, usually somewhat flesh- 

 colored and the akenes are either embedded in the torus as in F. 

 I'irginiaiia or borne on the surface as in F. vcsca. The strawberry 

 fruit contains about 87 per cent, of water; 6 per cent, of cane 

 sugar; 5 per cent, of invert sugar (a mixture of dextrose and 

 levulose) ; 1 per cent, of free fruit-acids; and about 2 per cent, 

 of nitrogenous substances. 



g. LEGUMINOS^ OR PULSE FAMILY. The plants 

 are herbs, shrubs, trees, or vines with alternate, stipulate and 

 usually compound leaves. The flowers are complete, and the 

 corolla is either regular or irregular; the stamens are usually 

 united, and the pistil is simple and free, becoming in fruit a 

 legume. The plants are widely distributed, many of them being 

 found in the Tropics. Three principal sub-groups, which have 

 been ranked as families by some botanists, are recognized. 



1. PAPiLibNAT.E. Those species with papilionaceous flowers 

 are separated into a group called the Papilionatae. This sub- 

 group has a number of representatives in the United States, as 

 clover, locust, and Baptisia (Fig. 134, L). 



2. CyESALPiNioiDE^ include the sennas and have flowers 

 which are nearly regular, or imperfectly, or not at all papiliona- 

 ceous. 



3. The MiMOSOiDE.E include the acacias and have flowers fliat 

 are regular. 



Cassia acutifoUa is a small shrub with leaves that are 8- to 

 10- foliate. The leaflets are official as Alexandria senna (p. 607) ; 

 the flowers are yellowish and in axillary racemes ; the fruit is a 

 smooth, flat, dehiscent pod, with 6 to 8 seeds (Fig. 262). 



Cassia angustifolia is a shrub which is cultivated in Southern 

 India and resembles Cassia acutifoUa. The leaflets which consti- 



