96 



DESCRIPTIVE BOTANY. 



Order XXI. LEGUMINOS^. 



Flowers irregular or regular, perfect. Sepals 5, more or less united, 

 unequal, the odd one anterior. Petals 5, odd one posterior. Stamens 

 distinct, or 9 united, and one (the posterior one) free. Ovary supe- 

 rior, single and simple. Style and stigma simple. Fruit a legume. 

 Leaves stipulate, usually compound. Herbs, shrubs, or trees. Num- 

 ber of genera, about 400. 



INDIGOFERA, L. (Indigo.) Calyx with 5 acute segments ; vexillum 

 roundish and emarginate ; keel with a spur on each side, at length 

 reflexed ; legume 2-valved, and 1- to many-seeded. Shrubs. 



I. tinctoria, L. (Indigo Plaut.) Stem 2 to 3 feet high, and from a 

 quarter to half an inch in diameter, subligneous, branching. Leaves com- 

 pound, consisting of about 6 pairs of longish 

 bluish-green leaflets, and a terminal soft one, 

 darker above ; flowers in axillary racemes, 

 papihonaceous and pale-red. July and Au- 

 gust. 



Species. — There are about 1 50 species of 

 this genus, most of which yield indigo, but 

 the species that are found to be most pro- 

 ductive are — 



1. I. tinctoria, L. (Coloring Indigofera.) 



2. I. argentea, N. (Silver-leaved Indigofera.) 



3. I. Caroliniana, L. (Carolina Indigofera.) 

 Besides the 1.50 species of A. De Can- 



dolle, there are as many or more varieties, 

 most of which yield this dye. 



The following plants also contain indigo : 



Nerium tinctorium, Kottb. (Apocynacese.) 



Tephrosia tinctoria, L. (Leguminosas.) 



Tephrosia apoUinea, L. 



Tephrosia toxicaria. 



Polygala tinctoria, Persoon. (Polygalaceae.) 



Polygonum Chinense, L. (Polygonaceae.) China. 



Polygonum tinctorium, L. China and Japan. 



Polygonum barbatum, L. 



Polygonum perfoliatum, L. 



Polygonum aviculare, L. 



"Wrightia tinctoria, R. Brown. (Apocynaceag.) India. 



Amorpha fruticosa, L. (Leguminosge.) 



Baptisia tinctoria, R. Br. (Leguminosse.) 



Marsdenia tinctoria. (Asclepiadaceae.) India. 



Randia aculeata. (Cinchonaceae.) West Indies. 



Geography. — The indigo-bearing plants flourish in a hot climate. The 

 Indigofera tinctoria is a native of India, and is cultivated between 20° and 30° 

 of north latitude. It is grown in Java, the East Indies, Northern Africa, the 

 West Indies, and Central America. That frum India and Central America ici 

 the most valuable. 



Indigofera tinctoria (Indigo), 



