96 NATURE STUDY AND AGRICULTURE 
These flowers and the pods which follow them are easily recog- 
nized as examples of the Mustard family. Grows in dry soil. 
31. Silver leaved Psoralea:  Silver- 
leaved Prairie Clover.— The whole plant 
is silky, silvery white, and quite decora- 
tive; bushy in form and 1 to 3 feet high. 
Flowers are small and purplish blue in color ; 
leaves are compound, with 3 to 5 leaflets. 
Flower and leaves show that it belongs to 
the Pea family. 
32. Yarrow. — A 
familiar plant, with 
Rae eas feathery leaves and small 
PSORALEA white flowers in dense, 
flat-topped clusters. The plant is gray- 
green in color and has a strong aromatic 
odor resembling that of tansy. The stem 
is a foot or two high and is unbranched 
except at the top. 
YARROW 
33. Sticks: Lygodes- 
mia. — A curious looking plant, all the lower 
leaves being so minute that it seems to be 
leafless, whence the name ‘‘ Sticks.” The 
plant is much branched and 10 or 12 inches 
high. The rose-purple flowers are composite, 
there being about 5 florets in a head. 
34. Blue Lettuce: Wild Lettuce. — May 
be identified by its pretty blue composite 
flowers and milky juice, and its smooth stem 
and leaves. The plant is from one to two 
feet high, and is common on wild prairie sod 
Bive Lerruce as well as in waste places. 
