LEGUMINOSAE 145 



AMORPHA Linnaeus 

 False-Indigo Shoestrings 



The false-indigos are shrubs with alternate, odd-pinnate 

 leaves, which are also glandular-punctate. The flowers are 

 perfect but incomplete and are borne in spikelike racemes. The 

 calyx has 5 lobes and is short, and the blue, purple or white 

 corolla lacks wings and keel. The banner is erect, clawed, and 

 folded around the 10 stamens, the filaments of which are united 

 at the base only. The ovary develops into a short, 1- to 

 2-seeded, nearly indehiscent pod. 



The false-indigos are limited in their distribution to North 

 America and Mexico. There are about 15 species, of which 

 only 2 occur in Illinois as shrubs. 



Key to the False-Indigo Species 



Tall shrubs, reaching a height of 3 to 12 feet; leaflets ^ to 



V/i inches long A. fruticosa 



Low shrubs, generally less than 3 feet high; leaflets mostly 



less than 3^ inch long A. canescens 



AMORPHA FRUTICOSA Linnaeus 

 Indigobush False-Indigo 



The Indigobush, fig. 34, is an erect shrub with gray or brown 

 bark and greenish branchlets, which become glabrous, or nearly 

 so, and light brown by autumn. The leaves are generally 8 to 

 12 inches long. They stand on petioles ]/[ to ^ inch long and 

 consist as a rule of 9 to 25 entire-margined leaflets which are 

 set in opposite or nearly opposite pairs well separated along 

 the rachis on stalks less than i/^ inch long. The leaflets are yi 

 to 11/2 inches long, oval or oblong, rounded or narrowed at the 

 base, and rounded and emarginate but mucronate at the tip. 

 At maturity, the surface is more or less pubescent on both sides 

 and is glandular-dotted beneath. 



The inflorescences, clusters of spikelike racemes, are borne 

 near the end of the branches. Sometimes the spikes are solitary. 

 The flowers, which open in May or June, are numerous, violet- 

 purple, and about \4, inch long. The fruit is a glabrous, gland- 

 ular pod generally 14 inch long or a little more, which usually 

 contains 2 seeds. 



Distribution. — The Indigobush prefers well-drained allu- 



