392 PLANT PHYSIOLOGY 



. Wenn stirbt die durch frost getotete Pfianze, zur zeit des Gefrierens 



Oder im Moment des Aiifthauens. Botan. Zeit., 29: 399-402, 1871. 



. tJber das Gefrieren, Erfrieren der Pflanzen und Schutzmittel 



dagegen. Stuttgart. Abst. botan. Jahresber., 11(2): 423-424, 1883. 



. tJber chemische Vorgange Beim Erfrieren der pflanzen. Landw. 



Vers.-Sta., 65: 149-160, 1907. 



GoRTNER, R. A. The state of water in colloidal and living systems. Col- 

 loid Science Applied to Biology. Trans. Faraday Soc. 26 : 678-686, 1930. 



and W. F. Hoffman. Determination of moisture content of 



expressed plant tissue fluids. Botan. Gaz., 74: 308-313, 1922. 



Greathouse, G. a., and N. W. Stuart. A study of the physical and 

 chemical properties of red clover roots in the cold-hardened and 

 unhardened condition. Md. Agr. Exp. Sta. Bull. 370, 1934. 



and . Unfreezable and freezable water equilibrium in plant 



tissues as influenced by sub-zero temperatures. Plant Physiol., 10: 

 781-788, 1935. 



and . The relation of physical properties and chemical com- 



position of red clover plants to winter hardiness, Md. Agr. Exp. Sta. 



Bull, 391: 465-492, 1936. 

 Harvey, R. B. Hardening process in plants and developments from frost 



injury. Jour. Agr. Res., 15: 83-112, 1918. 

 . Importance of epidermal coverings. Botan. Gaz., 67: 441-444, 



1919. 

 . Varietal differences in the resistance of cabbage and lettuce to 



low temperatures. Ecology, 3: 134-139, 1922. 

 . Red as a protective color in vegetation. Minn. Hort., 51: 279, 



1923. 

 . Cambial temperatures of trees in winter and their relation to sun 



scald. Ecology, 4: 261-265, 1923. 

 — . Conditions for heat canker and sunscald in plants. Minn. Hort., 



51: 331-333, 1923. 

 — . Relation of the color of bark to the temperature of the cambium 



in winter. Ecology, 4: 391-394, 1923. 

 — . Conditions for heat canker and sunscald in plants. Jour. For., 



23: 392-394, 1925. 

 — . Relation of the storage temperature to freezing injury in vege- 



tables. Minii. Hort., 57: 261-268, 1929. 

 — . Time and temperature factors in hardening plants. Am.. Jour. 



Botany, 17: 212-217, 1930. 

 — . Length of exposure to low'temperature as a factor in the hardening 



process in tree seedlings. Jour. Forestry, 28: 50-53, 1930. 

 — . Artificial refrigeration as a means of studying winter hardiness. 

 Jour. Am. Soc. Agron., 23: 16, 1931. 

 — . "An annotated bibliography of the low temperature relations of 



plants." Burgess Publishing Co., Minneapolis. 



— . Physiology of the adaptation of plants to low temperature. 

 Proc. World's Grain Exhibition Conference, Regina, Can., 2: 145-151, 

 1935. 



