ECONOMIC IMPORTANCE OF GRASSES 



127 



FIG. 51. Timothy (Phleum pratense). A, single spikelet; B, spikelet with glumes 

 removed; C, pistil. (Robbins.) 



-groove 



r r jiarcny 



i endosperm 



jKT 



"P^flflU^ ft aleurone- 



scuiellum * 

 coleoptile- 



/j 



xyl/ndnc 

 epithelium 



B 



drawing 

 'point 

 r oj .stem 



roof --- 

 coleorhiza 



PIG. 52. PIG. 53. 



PIG. 52. Diagram of A, lily flower, and B, grass flower showing homologous struc- 

 tures. A, f, bract; ax, axis; op, outer part of perigonium; ip, inner part of perigonium; 

 5, stamens; c, tricarpellary 3-celled ovary. B, shaded structures are aborted; le, glume 

 (bract); ax, axis; p,pa.\et, and p', lemma (outer perianth); / and./' lodicules (inner part 

 of perigonium) ; s and s', two whorls of stamens; c, tricarpellary i-celled ovary. (B. 

 Robbins after Schuster.) 



PIG. 53. Part of a median lengthwise section of a grain of wheat; much enlarged. 

 (Robbins after Strasburger.) 



