566 



BOTANY 



regarded as of recent origin. Flowers epigynous, with simple or 

 double perigone. 



Family Aristoloehiaeeae. — Flowers actinomorphic or more fre- 

 quently zygomorphic ; with simple corollaceous perigone consisting of 

 three coherent members ; androecium usually of six or twelve stamens, 

 which are either free or united to the style (gynostemium) ; ovary four- 

 to six-locular ; fruit a capsule. Herbs and lianes NOT parasitic. 



This family comprises chiefly tropical plants with cordate or reniform leaves, 

 represented in Europe and North America by the genera Asarum (Asarabacca, 

 "Wild Ginger) and Aristolochia (Birthwort). The European species of Asarum, 



A. europaea (Fig. 543), is a small 

 herb with brown flowers, having 

 an actinomorphic perigone and 

 free stamens. An example of the 

 genus Aristolochia is afforded by 

 A. CUmatitis, a large perennial 

 whose flowers have a zygomorphic 

 perigone and a gynostemium. 

 Aristolochia sipho, the Pipe-Vine 

 of North America, is a frequently 

 cultivated climber. 



The two families, Rafflesiaceae 

 and Balanophoraceae, are leafless, 

 often Fungus-like, root parasites 

 entirely devoid of chlorophyll. 

 The first -named family has soli- 

 tary flowers, often of an enormous 

 Fig. 544.— Vifcum album. 1, Part of shoot with female size. The flowers of Eafflesia 

 flowers and fruit ; 2, group of flowers ; 8, a male Amoldi (Sumatra) are the largest 

 .4, female flower cut through longitudinally ; of aU flowS) attain ing a diameter 



of 1 metre. The flowers of the 



-Poisonous. (After 



5, longitudinal section of fruit.- 

 Wossidlo.) 



Balanophoraceae, on the other 

 hand, are small and aggregated into dense heads or spikes. Both families are 

 almost exclusively confined to the Tropics. 



Family Santalaceae. — Flowers actinomorphic ; with a small greenish simple, 

 trimerous or pentamerous perigone ; androecium of a like number of stamens ; 

 ovary unilocular, with three ovules attached to a free central placenta. 

 Seeds without seed-coats. Terrestrial parasites with leaves. 



The plants included in this family are chiefly tropical, represented by herbs 

 and shrubs with inconspicuous flowers. Provided with leaves and growing on the 

 ground, they absorb a large part of their food ; their roots, however, develop 

 haustoria, which penetrate the roots of other plants, e.g. Thcsium linophyttum, the 

 Bastard Toad-flax. 



Officinal. — Santalum album, a parasitic tree growing in East India, yields 

 the valuable scented Sandal-wood, from which oil of sandal- wood, Oleum Santali, 

 is obtained by distillation. 



Family Loranthaeeae. — Flowers actinomorphic, with double, 

 corollaceous or calycoid, two- to three-merous perigone ; androecium 



