5 o8 



BOTANICAL GAZETTE 



[DECEMBER 



deleterious action of bog water was, on the whole, less marked upon 

 the tops than upon the roots. Nevertheless the green weight of 

 some of the plants with a lower transpiration value was greater than 

 that of the plants transpiring more strongly. Examples are num- 

 bers 3, 5, and 7 in table I; 2 and 5 in table II; 4 and 6 in table III; 

 7 and 10 in table IV. 



TABLE I 



Transpiration data of varieties of grain sorghums 8 in bog water 



March 6-24, 1910 



1. 



2. 



3- 

 4. 



5. 

 6. 



7. 

 8. 



1. 

 2. 



3- 

 4. 



5. 



Variety of sorghum 



Transpiration in 

 grams 



Green weight 

 produced 



Milo 



White Durra 

 Dwarf Milo . 



Dagdi Durra. . . . 

 White Kowliang. 

 Blackhull Kaffir. 

 Brown Kowliang 

 Red Kaffir 







106.15 



91. 



•05 



86 



.70 



78. 



95 



78. 



■32 



69 



95 



55 



65 



52 



.90 



Water required for 

 1 gram of 



green matter 



2-59 

 2.18 



2.87 



I.89 



2.92 



I.40 



I.46 



I.28 



40 

 42 



30 



41 

 26 



49 

 37 

 4i 



95 

 98 



17 

 70 



08 



85 

 98 



34 



Atmometer: 25 cc. daily average 



TABLE II 



Transpir 



P 



May 6-26, 1910 



Variety of alfalfa 



Medicago falcata 



Var. 16399 (Washington) . . . 



Var. 23625 



Var. 9359 (Turkestan) 



Sand Lucerne 20457 



Transpiration in 

 grams 



II.50 



11.86 

 8.72 



7.3 2 

 H-93 



Green weight 

 produced 



I.48 

 2.28 

 O.99 



0-59 



2.21 



Water required for 



1 gram of 



green matter 



7-77 

 5.20 



8.80 



12.40 



5-40 



Atmometer: 18.9 cc. daily average 



It is quite generally known that rapid growth is usually accom- 

 panied by active respiration, and hence slowly developing plants 

 are able to increase in dry weight upon a smaller quantity of water 

 absorbed and transpired. It seems clear from the normal appear- 

 ance of the roots of these plants, that the injurious substances have 

 an entirely different effect upon some varieties of the plants with 



8 Ball, C. R., The history and distribution of sorghum. U.S. Dept. of Agricul- 

 ture, Bur. Plant Industry, Bull 175, 19 10. 



