Hitchcock — Ecological Plant Geography of Kansas. 63 



In the western part of the State some of these disappear 

 and the following become common : Oleomella angusti 'folia, 

 Talinum calycinum, Indigo f era leptosepala (S. W. Kansas), 

 Gaura villosa, Mentzelia mulliflora, Erigeron diver gens, 

 Aster tanacetifolius, Hymenopappus flavescens, Polypteris 

 Hooheriana, Gaillardia pulchella, G. aristata, Artemisia fill- 

 folius, Gilia aggregata, Heliolropium convolvulaceum, Kry- 

 nilzkia Jamesii, Asclepias arenaria, Physalis lanceolata pu- 

 mila, P. hederaefolia, Oxybaphus sp. (allied to O. albidus), 

 Abronia fra grans, Corispewnum hyssopi folium, Eriogonum 

 annuum, Euphorbia Geyeri, E. petaloidea, Slillingia syl- 

 vatica, Commelina angusti folia , Andropogon Hallii, 8tipa 

 comata, Redfieldia flexuosa, Gymnopogon racemosa (S. 

 Kansas), Eragrostis oxylepis. 



A large number of the species are not found, within our 

 limits, in any other than sandy soil. Several plants that are 

 characteristic of the plains in west Kansas extend eastward in 

 the sand-hills, such as Ipomoea leptophylla. Some plants of 

 the surrounding prairie may extend more or less into the 

 sand-hills, such as Ambrosia psilostachy a. The cactuses are 

 rarely found in the sand-hills. 



A large proportion of the species are annual. The peren- 

 nial plants frequently have extensively creeping root-stocks, 

 such as the binding grasses mentioned. Others form deep 

 slender roots which appear to reach down to permanent 

 moisture, as Physalis and Asclepias. Artemisia forms a thick 

 crown and helps materially in retarding the shifting sand, as 

 do some of the bunch grasses. Ipomoea leptophylla and 

 Cycloloma are tumble weeds. 



In the eastern sand-hills a shrub, Prunus angustifolia, fre- 

 quently forms quite extensive thickets which tend to bind the 

 sand. Amorpha canescens is also frequent. This small shrub 

 is also common on the prairie. 



CLASS VII. PRAIRIE. 



Prairie is more extensive than all the other formations 

 together. The western half of the State is in the region 

 known a3 the Great Plains, which extends west to the moun- 

 tains, south into Texas and far northward. In this region the 



