Yellow and Orange 



Yellow or Hop Clover 



(Trifolium agrarium) Pea family 



Flowers Yellow, scale-like, overlapping in a densely many-flow- 

 ered oblong head about % in. long, becoming brown with 

 age. Stem: Ascending, branched, 6 to 18 in. high. Leaves: 

 3-foliate, very finely toothed. 



Preferred Habitat Waste places, fields, roadsides. 



Flowering Season May September. 



Distribution Virginia to Iowa, and far northward. 



What did the sulphur butterflies provide as food for their 

 caterpillar babies before the commonest clovers came over from the 

 Old World to possess the soil ? Wherever a trifolium grows, there 

 one is sure to see 



" Sallow-yellow butterflies, 

 Like blooms of lorn primroses blowing loose, 

 When autumn winds arise." 



The Blackseed Hop Clover, Black or Hop Medic (Medicago 

 lupulina), with even smaller, bright yellow oblong heads which 

 turn black when ripe, lies on the ground, its branches spreading 

 where they leave the root. A native of Europe and Asia, it is now 

 distributed as a common weed throughout our area, for there is 

 scarcely a month in the year when it does not bloom and set seed. 

 It is still another of the many plants known as the shamrock. 



Yellow Wood-sorrel; Lady's Sorrel 



(Oxalis strictd) Wood-sorrel family 



Flowers Golden, fragrant, in long peduncled, small, terminal 

 groups. Calyx of 5 sepals; corolla of 5 petals, usually reddish 

 at base ; stamens, 10 ; I pistil with 5 styles ; followed by 

 slender pods. Stem: Pale, erect, 3 to 12 in. high, the sap 

 sour. Leaves: Palmately compound, of 3 heart-shaped, 

 clover-like leaflets on long petioles. 



Preferred Habitat Open woodlands, waste or cultivated soil, road- 

 sides. 



Flowering Season April October. 



Distribution Nova Scotia and Dakota westward to the Gulf of 

 Mexico. 



An extremely common little weed, whose peculiarly sensitive 

 leaves children delight to set in motion by rubbing, or to chew for 

 the sour juice. Concerning the night "sleep" of wood-sorrel 

 leaves and the two kinds of flowers these plants bear, see pages 

 107 to 1 10. 



3" 



