340 BOTANY AND PHARMACOGNOSY. 



several species of Pangiiim are used in cooking. A bitter principle 

 occurs in the bark of Casearia adstringens of Brazil. A purgative 

 principle is found in C. esculenta of tropical Asia and Australia. 

 The root of Homalium racemosum of Guiana contains an astrin- 

 gent principle. 



1. FAMILY TURNERACE^.— These plants are herbs, 

 shrubs and trees mostly found in tropical America, and are of 

 interest on account of the leaves of Turnera diffusa, particularly 

 the variety aphrodisiaca, which yield the Damiana of medicine 

 esteemed as a tonic laxative like Rhamnus Purshiana. The drug 

 usually consists of leaves although the reddish stems, yellowish 

 flowers and globular capsules may be present. The leaves are about 

 25 mm. long, varying from oblanceolate to obovate ; the margin is 

 serrate-dentate ; the color, light-green (older leaves somewhat cori- 

 aceous and pubescent) ; the odor aromatic; taste aromatic and bit- 

 ter. Damiana contains a volatile oil, resin, and the bitter principle 

 damianin. Ethereal oils are found in other species of Turnera, 

 and T. angustifolia of Mexico contains considerable mucilage. 



m. PASSIFLORACE^ OR PASSION-FLOWER FAM- 

 ILY. — The plants are mostly herbaceous or woody vines climbing 

 by means of tendrils, with alternate, palmately-lobed, petiolate 

 leaves and solitary, perfect, regular flowers. The flowers are 

 peculiar in that between the corolla and stamens there are numer- 

 ous, frequently petaloid, colored, sterile, filamentous bodies which 

 are known collectively as the "corona." The fruit is a berry or 

 dehiscent capsule. The genus Passiflora is known as the Passion- 

 flower because the flowers are considered to be emblematic of the 

 Crucifixion, the corona representing the crown of thorns, the 

 stamens the nails, and the gynsecium with its three styles, the 

 three thieves. The rhizomes of the Passion-flowers of the South- 

 ern States (Passiflora incarnata and P. lutea) have been used in 

 medicine. Not much is known with regard to the active principles 

 of these two plants or of the thirty other species of Passiflora which 

 are used in medicine. The fruits of several species of Passi- 

 flora are edible, and a number of them are cultivated on account 

 of their beautiful as well as odorous flowers. 



n. CARICACEiE OR PAPAW FAMILY.— This family is 

 composed of two genera of latex-containing trees growing in trop- 



