706 DIOSCOREACE. 
dyeing agents in North America, others are edible, and a few 
are bitter and astringent. 
Aletris farinosa is remarkable for its bitterness. It is reputed to possess 
tonic and stomachic properties. 
Hezmodorum.—The roots of several species, as those of H. paniculatum 
and H. spicatum, when roasted, are eaten by the natives in some parts of 
Australia. The root contains a red colouring matter. 
Lachnanthes tinctoria has a blood-red root which is used for dyeing in 
North America. 
Cohort 6. Dioscorales.—F lowers unisexual and dicecious, regular. 
Perianth herbaceous. Stamens 6, inserted at the base of 
the perianth-segments. Ovary 3-celled ; placentation axile. 
Fruit baccate or capsular. Seeds with abundant fleshy 
albumen and a distinct included embryo. Climbing herbs 
or small twining shrubs, with netted-veined leaves. 
Order 1. DioscorEACE#, the Yam Order.—Character.— 
Climbing herbs, or small shrubs, with twining stems rising from 
tuberous rootstocks or tubers, placed above or under the ground. 
Leaves net-veined, stalked. Flowers unisexual, dicecious, small, 
bracteated. Male flower :—Perianth 6-cleft. Stamens 6, inserted 
at the base of the perianth-segments. Female flower :—Perianth 
superior, 6-partite. Stamens sometimes present, but very short 
andabortive. Ovary inferior, 3-celled ; styles 3, distinct, or 1, and 
then deeply trifid ; ovwles 1—-2 in each cell, suspended. Fruit 
dehiscent and compressed, or fleshy and indehiscent, 1—3-celled. 
Seeds albuminous ; embryo small, in a cavity in the albumen. 
Distribution and Numbers. —Chiefly tropical plants. Tamus 
communis is, however found in Britain and other temperate 
regions. Illustrative Genera :—Tamus, Linn. ; Dioscorea, Linn. 
There are above 150 species. . 
Properties and Uses.—The plants generally contain an acrid 
principle. The tuberous rootstocks of many species of Dioscorea 
are, however, when boiled, used for food in tropical countries. 
Dioscorea.—The tuberous rootstocks 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 (D. Batatas) is now cultivated 
in this country, and when properly boiled is esteemed by many as an escu- 
lent. Some species of Dioscorea are very acrid even when boiled, and cannot 
therefore be used for food. The rhizome of D. villosa, the Wild Yam of the 
United States, is regarded as a valuable remedy in Virginia in rheumatism, 
and is hence commonly known as ‘rheumatism root.’ It has also been recom- 
mended in bilious colic. 
Tamus.—T. communis, Common Black Bryony, has a large fleshy root 
which when fresh possesses considerable acridity. It is sometimes used as 
a topical application to bruised parts to remove the marks. Taken inter- 
nally, it acts as a diuretic, and also, it is said, as an emetic and cathartic. 
The young shoots of this species and those of 7. cretica, when thoroughly 
boiled, so that their aeridity is destroyed, have been eaten like asparagus. 
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 the Tor- 
toies plant ; the inner part of this stem is very mealy, and is used for food 
by the Hottentots 
