MORPHOLOGY OF HIGHER PLANTS. 



423 



VI. THE OUTER MORPHOLOGY OF THE SEED. 

 The seed may be defined as the fertilized and developed ovule. 

 The seeds of different fruits vary in number as well as in size 



FIG. 247. Transverse (I) and longitudinal (II) sections of oat grain (Avena sativa): 

 i, 2, cells of pericarp; 3, seed-coat; 4, remains of perisperm; 5, cells containing gluten; 

 7. endosperm cells containing considerable proteins and some starch; 6, endosperm cells 

 With polygonal compound starch grains; 8, fibro vascular bundle of the pericarp. After Harz. 



and shape. In form they correspond to the ovules; in size they 

 vary from about 0.600 mm., as in lobelia, belladonna, etc., to 10 or 

 15 centimeters in diameter, as in the co-coanut palm. Seldom are 



