BOTANICAL CHARACTERS 



81 



at one time; 15 is usually considered a desirable number. CHAP, 

 The average number for 313 plants ' at the Botanical Experi- IV ' 

 merit Station, Pretoria, in 1907-8 was 103, the maximum 

 being 14 (on 3 plants only) and the minimum 6 (on 2 plants 

 only). Leaf measurements were made of these 313 plants, 

 the sixth from the base was selected as the most fully de- 



blade. 



Fig. 25. — Leaf sheath and base of blade, showing ligules, and hairs on 



veloped ; the maximum width was 5-25 inches, the minimum 

 2 '5 inches, and the average 3 '8 inches. 



The total external leaf-surface of a single maize plant has 

 been measured, at the Missouri State Experiment Station, and 

 found to equal 24 square feet. An acre often carries over 



1 Of a cross between Iowa Silver-mine and Wisconsin white dent. 



6 



