FAMILIES OF FLOWERING PLANTS 137 
shape of the keel itself is found to vary; the peculiar snout-like shape 
of the keel in the bean flower is well known. We shall follow the sys- 
tematic arrangement of the tribes in this family, taking a hasty survey 
of such genera as are of special importance. 
In the tribe Sophoreae the yellow-wood (Cladrastis lutea) of our 
southern States, furnishes us both with a highly ornamental tree and a 
yellow dye. Several exotic species of Sophora are cultivated in gar- 
dens, while the South American 
genus Myroxylon yields a fine bal- 
sam. 
Tribe Podalyrieae. This con- 
sists mostly of shrubs with simple 
or palmately divided leaves. It in- 
cludes our various wild false indi- 
goes (Baptisia) and the largeAus- 
tralian genus Pultenaea. 
Tribe Genisteae. In this group 
are a number of well known Euro- 
pean plants, such as the “golden 
shower (Laburnum vulgare), the 
Scotch whin or gorse (Ulex), the 
broom (Cytisus scoparius), and the 
woad-waxen or dyer’s weed (Genista 
tinctoria). Several of these have be- 
come naturalized in the United 
States; but the important American 
genus of this tribe is Lupinus, the Fig. 120, Wild lupine, Lupinus perennis. 
lupines, comprising al arge n umber After Britton & Brown, Ill. Fl. Northeast. U. S. 
of species throughout the western plains and along the Pacific coast. 
Fig. 120 shows the only lupine of the northeastern States (L. perennis). 
In Florida occur two species with apparently simple leaves, but in 
reality the leaf is a compound one reduced to a single leaflet, as shown 
by the joint between blade and stalk. The genus Crotalaria is also a 
large one, and widely distributed through warm regions. The inner 
bark of C. juncea, the “sunn” or Bombay hemp of India, yields a valu- 
able fiber. 
Tribe Trifolieae. This includes the true clovers (Trifolium), the 
yellow hop-clover (Chrysaspis), the alfalfas (Medicago), and the sweet 
clovers (Melilotus). In Europe are found also the “rest-harrows” 
(Ononis), and the fenugreeks (T'rigonella). All clover-like plants may 
be known by the close heads or spikes of small flowers, and by the usu- 
ally palmate leaves. Those of cold or alpine regions are usually her- 
baceous, while those of the warmer temperate zone are often shrubs or 
