I40 THE OSMOTIC QUANTITIES OF PLANT CELLS 



TABLE 1 8 OSMOTIC PRESSURES OF THE LEAVES OF VARIOUS SPECIES 



(data of HARRIS, I934, AND MEYER, I927) 



Species 



Ligneous species 



Black Locust 



Black Walnut 



Cottonwood 



Dogwood 



Loblolly Pine (summer) 



Mountain Laurel 



Pitch Pine (summer). . . 



Red Maple 



Sassafras 



Scarlet Oak 



Sweet Gum 



Sycamore 



Tree-of-Heaven 



Tulip Tree 



White Ash 



White Oak 



Willow 



Yellow Birch 



Robinia pseudacacia 

 Juglans nigra 

 Populus deltoides 

 Cornus florida 

 Pinus taeda 

 Kalmia latijolia 

 Pinus rigida 

 Acer rubrum 

 Sassafras sassafras 

 Quercus coccinea 

 Liqiiidambar styraciflua 

 Platanus occidentalis 

 Ailanthus glandulosa 

 Liriodendron tulipijera 

 Fraxinus americana 

 Quercus alba 

 Salix alba 

 Be tula lute a 



Herbaceous species 



Blue Grass 



Burdock 



Cat-tail 



Chickweed 



Cinnamon Fern . . 



Cocklebur 



Dandelion 



Jack-in-the-Pulpit 



Mullein 



Patience Dock. . . 



Pokeweed 



Soapwort 



Sunflower 



Touch-me-not. . . . 

 Wandering Jew. . 

 Water Lily 



Poa pratensis 

 Arctium minus 

 Typha latijolia 

 A Is in e media 

 Osmunda cinnamomea 

 Xanthium sp. 

 Taraxacum taraxacum 

 Arisaema triphyllum 

 Verbascum thapsus 

 Rumex patientia 

 Phytolacca decandra 

 Saponaria officinalis 

 Helianthus annuus 

 Impatiens biflora 

 Zebrina pendula 

 Castalia odorata 



Osmotic 

 pressure 

 (atmos.) 



12.6 

 14.6 

 21.3 



17- 

 li 



li 



li 



17- 

 20.4 



19. 1 



15-5 

 12. 1 



16.9 



16.0 



16.4 



20.4 



II. 4 



15. 1 



13 

 10 

 II 



7 



10 

 II 



13 

 8 



13 

 6 



8 



II 



18 



7 



4 



14 



equilibrium towards the side of the soluble carbohydrates (Chap. XXII). 

 The effects of different soil water contents on the osmotic pressure of the 

 tops and roots of maize plants are illustrated in Table 19. 



