2.51 THE STRUCTURE OF ECONOMIC PLANTS 



fruit coats of the "seed ball" and grows directly downward with- 

 out branching. The hypocotyledonary arch elongates, lifting the 

 cotyledons above the soil; and, finally, the hypocotyl straightens 



h - 



funiculus 



^ cotyledons 



endosperm 



seed coat 



Fig. iio. A-B, diagrams of sugar beet seed showing distribution of vascular tissues ; C, 

 section of mature seed with embryo in longisection ; D, transection made along axis a-a in 

 C\ E-I, successive transections made parallel to axis b-b in C; £ is the lowest section. In 

 figures C-I, xylem is shown in solid black, phloem by heavy stipples, and tannin-containing 

 cells by circles. (After Bennett and Esau, Jour. Agr. R«.r.) 



