DIOSCOKKACE^. 271 



crowned witli i>urple olliptii-al segments. Stigmas long, emarginate, red ur 

 deep orange, extending beyond the tuhe. 



There are many other species, but the sativiis is the most important. 



Geo;/raphij. — The geographical range is tiiroughout the southern parts of 

 the north temperate zone. 



Etyinologji. — Crocus, the generic name, was given to this plant by Theo- 

 phrastus, but tlie meaning is obscure. Satlvus is Latin for " sown " or 

 " cultivated." 



History. — This plant was known to the ancients; it is mentioned by 

 Dioscorides, Theoi)hrastus, and Pliny. The Romans cultivated it fur its per- 

 fume ; and in later times it was an important crop in England. The parts 

 producing the dye are the style and stigma; and it has been estimated that 

 a single pound of saffron is composed of the stigmas of 200,000 flowers. 



Use. — The medicinal properties are not important. It was formerlv admin- 

 istered in infusions in a multitude of disorders, but especially to bring eruptive 

 diseases to the surface. Modern practice has brought in remedies which have 

 crowded it out. 



There are two active principles contained in saffron flowers : an oil to which 

 its flavoring and medicinal properties are due ; and a coloring substance which 

 furnishes the dye. 



As a coloring agent saffron is now used to color creams and biscuits, and to 

 color and flavor confectionery and cordials. As a dye, it is an important sub- 

 stance. The dye is produced by the presence of a principle which the 

 chemists call polychroite ; this substance, when brought into contact with 

 different chemical reagents, produces a variety of beautiful colors and tints. 



Order LVIII. DIOSCOREACE^. 



Flowers dioecious, small, inconspicuous, regular, in axillary racemes 

 or spikes. Perianth herbaceous, petal-like, in 6 parts, 2 seriate, equal, 

 and persistent. Stamens 6, inserted at the base of the segments of 

 the perianth ; filaments short, free. Ovary inferior, 3-celled ; styles ;3, 

 short ; stigma blunt or 2-lobed ; ovules 1-2 in each cell. Fruit cap- 

 sular, 3-angled or winged, 3-celIed ; seeds compressed, winged. Leaves 

 alternate or opposite, petioled, simple, prominently palminerved. 

 entire or lobed. Perennial herbs, with twining stems; tuberous, 

 fleshy roots. 



Xo. of genera. 8; species, 160; chiefly tropical. 



DI03C0REA, L. Flowers small ; stamens 6, at the base of the peri- 

 anth ; filaments awl-shaped. Styles of the fertile flowers '■) ; cells of 

 the capsule usually 2-seeded. Seeds margined by thin membrane ; 

 pods 3-angled. 



1. D. sativa, L. (Yam.) Stem long, slender, terete, smooth, twining or 

 clambering over shrubbery. Leaves alternate, broad, ovate-cordate, glabrous, 

 nerved, outer nerves forked, margin sinuate. Flowers in dense, axillary 

 spikes, greenish-white. Root gives rise to large edible tubers. 



2. D. batatas, Decaisne. (Chinese Yam.) Stem very long, resembling that 

 of D. sativa. Leaves opposite, smooth, lieart-shaped or halbert-shaped, in the 



