DICTTOGEN.E. 663 



principle. The tuberous root-stocks of many species of Dioscorea 

 are used for food in tropical countries. 



Tamus communis. Common Black Bryony, has a large fleshy root possess- 

 ing when fresh considerable acridity. It is sometimes used as a topical appli- 

 cation to bruised parts to remove the marks. Taken internally, it acts as a 

 diuretic, and also, it is said, as an emetic and cathartic. The young shoots of 

 this species, and those of T. cre^jca.when boiled, have been eateii like asparagus, 

 but when used in this way, care must be taken to have them thoroughly 

 boiled to get rid of their acridity. 



Dioscorea. — The tuberous root-stocks of several species, as those of D. 

 alata, D. sativa, and D. aculeata, when boiled, are eaten in tropical countries, 

 as potatoes are in Europe. The Chinese Yam is now cultivated in this country, 

 and when properly boiled, is much esteemed by many as an esculent Some 

 species of Dioscorea are very acrid even when boiled, and cannot therefore be 

 used for food. 



Testudinaria elephantipes, a native of the Cape of Good Hope, has a very 

 peculiar tuberous stem, hence it has been called Elephant's foot or Tortoise 

 plant. The inner part of this above ground tuber is very mealy, and is used 

 for food by the Hottentots. 



Natural Order 243. SsHLACE-a: — The Sarsaparilla Order. — 

 Herbs or shrubs, more or less climbing {fig. 1028). Leaves 



Fig, 1028.- 



Fig. 1028. A portioa of a branch, with leaves and fruit of SmUax papyraxxcu 



petiolate (Jig. 1028), net-veined, articulated. Flowers regular, 

 unisexual and dioecious, or hermaphrodite. Perianth inferior, 

 6-parted, with all its divisions alike. Stamens 6, perigynous 

 or rarely hypogynous ; anthers introrse. Ovary superior, 

 3-celled ; stigmas 3. Fruit a berry (fig. 1028), few or many- 

 seeded. Seeds with a minute embryo, albuminous. 



Distribution, ^c. — The species are scattered over various parts 

 of the world, both in tropical and temperate climates. They 

 are, however, most abundant in tropical America. Examples : 

 — Smilax, Ripogonum. There are 4 genera, and about 120 

 species, according to Lindley. Other botanists make the number 

 of species considerably more. 



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