7 8 MAIZE 



chap, in maintaining it in an erect position. Because they differ 

 from the stems of other families of plants, the stems of grasses 

 are usually spoken of as culms. 



The stem or culm of the maize plant is extremely variable 

 in height, ranging from \\ to 30 feet in different breeds and 

 in different climates ; the usual range in South Africa is from 

 about 5 to 14 feet. At the Botanical Experiment Station, 

 Pretoria, in 1907-8, the maximum height 1 was 6 feet 6 inches 

 (2 plants), and the minimum 3 feet, while the average of 313 

 plants was 5 feet 4 inches. The circumference of an average 

 stem ranges from about 3 to \\ inches between the first and 

 second nodes, in a dent or flint maize. 



The internodes are channelled on alternate sides, next 

 the leaf blade, and on the side where the branch or ear may 

 occur. 



The histology of the maize stem has been studied by Dr. 

 Cavers (1), whose illustrations of the tissues are reproduced here 

 (Figs. 19 to 22), by kind permission. Figs. 19 and 20 show 

 transverse sections through one of the lower internodes, and 

 21 and 22 longitudinal sections. 



The function of the stem is to carry food materials from 

 the roots to the leaves, and then to other parts of the plant, 

 and to raise the leaves and inflorescences into the air and light, 

 to facilitate photosynthesis (IT 69) and pollination (H J5). 



68. Sucker-shoots. — The maize plant often produces sucker- 

 shoots (Fig. 23), especially when planted thinly; these are 

 branches which arise from the lower nodes near or below the 

 surface of the soil. Some breeds have a much greater tendency 

 to sucker than others ; the tendency appears to be specially 

 strong in cross-bred plants. These suckers often produce 

 tassels bearing both male and female flowers (Fig. 24), which 

 sometimes develop small, round grains. As a rule suckers 

 do not bear proper ears ; they are, therefore, undesirable in 

 crops grown for grain, because they take food and moisture 

 from the soil and give no return except the fodder. Some 

 breeds bear several branches from nodes higher up the stem, 

 but as a rule the stems are unbranched except for the suckers 

 and the shanks of the ears, for the shanks are in reality only 

 short branches. 



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



