244 BOTANY AND PHARMACOGNOSY. 



Curcuma or turmeric is the rhizome of Curcuma longa, a 

 reed-like plant which is largely cultivated in India and other 

 tropical countries. In preparing the rhizome for market it is sub- 

 jected to a scalding or par-boiling process which agglutinates the 

 starch in the cells. While turmeric is used as a condiment it is 

 also used on account of its color as an adulterant of mustard and 

 other articles, but is very easily detected (Fig. 290). Several 

 forms of curcuma are found in commerce, as " round curcuma," 

 consisting of the main rhizome, and " long curcuma," composed 

 of the short branches. They occyr in cylindrical or ovoid pieces, 

 2 to 5 cm. long, of a yellowish-brown color externally, bright yel- 

 low internally, and aromatic odor and taste. Curcuma contains i 

 per cent, of volatile oil containing phellandrene and turmerol ; 0.3 

 per cent, of a yellow crystalline principle, curcumin, which is 

 soluble in alcohol, sparingly soluble in water, forms reddish-brown 

 solutions with alkalies and is converted into vanillin with weak 

 oxidizing agents. It also contains considerable starch and a srnall 

 quantity of an alkaloid. \ 



Other families of the Scitamineas are of great importance on 

 account of the food-products obtained from them, as the Musa- 

 cecB which contains the group of plants to which the banana 

 (Musa paradisiaca and M. Sapientum) belongs. To the Can- 

 nacecF belong the cultivated Cannas, one of them, Canna edulis, 

 being grown extensively in the West Indies and Australia as a 

 vegetable, and another, Canna coccinea, which grows in the West 

 Indies and South America furnishing " Tous les mois,'' the 

 arrow-root starch of the English and French. To the Maranta- 

 cece belongs Maranta ariindinacea, which is cultivated in tropical 

 America, and the rhizome of which yields the starch, Maranta 

 ARROWROOT (Fig. 3 1 6, B) . 



VII. ORDER ORCHIDALES OR MICROSPERM^. 



The most important family of this order is the Orchidace^ or 

 Orchid Family. The orchids are the most highly specialized 

 of the Monocotyledons. They are perennial herbs with diverse 

 habits, many tropical species being epiphytes, and varying morpho- 

 logical structure which is particularly evident in the zygomorphic 



