166 IOWA ACADEMY OF SCIENCES. 



life processes of the plant. A smooth leaf soon has its 

 stoniat.i filled with dust. On the other hand the hairs on 

 leaves serve to hold this dust. 



Protected plants. Sucli plants as Ap pi o pappus spinuloses, 

 Oxj/tropis Lamhertii, Lithospermiun cancscens, L. angusti- 

 folium, Psoralea argophylla, Gaura coccinea, Dalea alopecur- 

 oides are v^ell protected from the driving winds of summer 

 and fall. 



Of the plants needing much moisture and commonly 

 growing in open woods of the eastern section of the state 

 but rare or wanting in western Iowa, mention may be made 

 of the following: 



Podophyulluni peltatum. Fragaria vesca. 



Heracleum lanatuni (rare) . Mertensia Virginica. 



Caulophyllum thalictroides (rare) . Lobelia cardinalis. 



Solidago laii folia. Lobelia in f lata. 



Dodtcatheon media. Hydrophyllurn appe7idiculatum. 



Beep rooted plants. An equally instructive list of plants 

 may be added to show how some plants have protected 

 themselves from the injurious influences of wind and 

 drouth by producing deep roots. These roots are some- 

 times several feet long. 



Dalea laxi flora. Oxyttropis Lainbertii. 



Psoralea esculentu . Astragalus loti floras var. brachypus. 



Lygodesmia juncea . Cnicus canescens . 



Lactuca ptilchella. Gaura coccinea 



Aplopappus spitiulosus . Sporobolus cuspidatus. 



Yucca angustifolia . Asclepias tuberosa. 



Transpiration reduced. As a protection against transpira- 

 tion the leaves of many plants are hairy or reduced in size. 

 Of the hairy leaved plants we may mention the following: 



Convolvulus sepiufn. Oxyttropis Lanibertii. 



Asclepias verticillata . Castilleia sessi flora. 



Cnicus canescens . Gaura parvi flora . 



Cnicus lowensis . Salvia lanceolata. 



Aplopappus spinulosus. Plantago Patagonia var. gnapalioides 



Euphorbia niarginata . Asclepias speciosa. 



Achillea millet olium. 



Xerophytic grasses. The Xerophytic grasses of the loess 

 mounds are especially characterized by their reduction of 



