i84 THE STRUCTURE OF ECONOMIC PLANTS 



of the short stem axis. The epicotyl is surrounded by the basal 

 sheath of the cotyledon and may bear a single, slightly developed 

 leaf primordium prior to germination. (Fig. 83, G.) Near the 

 base of the cotyledon there is a lateral slit leading into the cavity 

 which, according to Sachs (15), occurs with equal frequency on the 

 convex and the concave sides of the embryo. In his description of 



Fig. 84. A, transection of a portion of seed showing principal regions ; B, surface view of 

 the epidermis and parenchymatous region : end, endosperm ; ep, epidermis ; par, paren- 

 chyma; p g, protein granules; psm, perisperm. (Redrawn and rearranged after Kondo, 

 Ohara Institute.) 



the embryo, as seen in longisection, he recognizes five regions: (i) 

 The peripheral or epidermal layer of thin-walled, parenchymatous 

 cells. These are arranged in longitudinal rows covering the root 

 and cotyledon; and, in the latter, stomata with guard cells may be 

 found, (x) The parenchyma of the hypocotyl and cotyledons. 



(3) The single provascular strand which can be recognized by the 

 long narrow cells that are filled with an albuminous material. 



(4) The meristematic regions occurring at the root tip and at the 

 growing point of the epicotyl; and (5) the well-defined root cap. 



