84 STUDIES IN THE VEGETATION OF THE STATE 



are arranged with reference to morning and evening light. 

 Lespedesa capitata is a strict, silky-canescent perennial oc- 

 curring infrequently in low prairies and meadows. In quad- 

 rats I, II, and IV of low prairies and meadows it averages 

 55 individuals, while in quadrats XXII, XXIV, XXV, and 

 XXVII of low meadows it averages but three. When abun- 

 dant it becomes rather a prominent factor in the floral cover- 

 ing on account of its size, color, and aggregation of plants. 

 The capitate clusters of small flowers do not add to the prom- 

 inence of the plant in the aspect. L. capitata is also an in- 

 habitant of high, dry prairies and bluffs along the Missouri 

 river. 



Silphium integrifolium and Vernonia gigantea are two 

 tall, leafy perennials of low meadows and edges of sloughs. 

 In such situations the iron-weed ranges from 15-65 individ- 

 uals per quadrat and the rosin-weed from 15-100. Silphium 

 frequently grows in dense impenetrable clumps which empha- 

 size all the more its prominence. These two species form 

 a zone about 30 meters wide in the wet meadow, and similar 

 zones in other parts of the formation. In these zones Sil- 

 phium invariably occupies the inside, next to, but never in- 

 vading, the Spartina facies, while Vernonia begins about the 

 middle and extends in diminishing numbers to the outside, 

 where it ends in scattered bunches. During July and Au- 

 gust these zones are prominent features in the formation, 

 from the masses of yellow flowers of SilpMum within, and the 

 purple flowers of Vernonia without, the two colors blending 

 at the center. V. gigantea occurs abundantly in low pastures,^ 

 frequently in company with V. fasciculata. 



Two hydrophytes, Cicuta maculata and Asclepias incar- 

 nata, occur sparsely in the sedge meadow. The large, leafy, 

 robust individuals of C. maculata tend to grow in groups; 

 its numerous white-flowered umbels continue during July 

 and are in striking contrast with the rose-purple of the 

 swamp milkweed. Both plants are perennials, the water 

 hemlock developing fleshy tuber-like roots. Another inhab- 



