LEGUMINOSAE (PULSE FAMILY) 223 
hay than in those that are green in the field. Its action is slow, 
often several weeks intervening before death. If recovery comes it 
is not complete, the animal being never so well again as before the 
attack of Crotalism. The weed is a relative of the dreaded Loco- 
weed of the plains, but does not cause the animals to “go plumb 
crazy,” as does that plant. (Fig. 159.) 
The plant is small, seldom more than a foot in height, with a 
much-branched and hairy stem growing 
from a small, straight root. Leaves 
alternate, nearly sessile, lance-shaped, 
one or two inches long, pointed at both 
ends, entire or slightly wavy, with edges 
softly hairy; they have curious stipules, 
shaped like an arrow-head, point down, 
with the ears sticking up on each side of 
the leaf and the point decurrent on the 
stem for a part of its length. Flowers 
yellow and very small, shaped like pea- 
blossoms, that is, with a corolla of five 
irregular petals, the upper one larger 
than the others, and enclosing them in 
the bud; this broad upright petal is 
called the standard and is usually turned 
backward ; two lateral petals or wings, 
obliquely spread and outside of the 
two lower ones which cohere at their 
edges, forming the keel, which usually Fis. 159. — Rattlebox (Cro- 
encloses the stamens and pistil. In this Enna SOmNpE see 
species the stamens are ten, one separate and nine of them united 
into a tube, cleft on its upper side, the anthers of two lengths and 
sizes, alternating with each other; calyx two-lipped, the two 
upper lobes broadest, all five long-pointed and softly hairy. The 
flowers grow in clusters of two or three on slender, axillary pe- 
duncles. Pods black, very hard and brittle, about an inch long 
but swollen much larger than the small, black seeds within, which 
break from their hold when ripe and rattle about inside the stiff, 
thin walls. In winter these light pods are blown long distances 
over the snow, and they can float like a boat on water. 
