38 BIOLOGY FOR BEGINNERS 



and not a single fruit like a bean pod. The chaff around the grains 

 represents some of the outer flower parts while the silk is a portion 

 of the central organ of the flower called the pistil, and its function 

 is to catch and transmit the pollen grains. This will be explained 

 in the chapter on fertilization. The husks are modified leaves 

 developed to protect the corn ear. 



Bean Corn 



Has hilum, testa, micropyle Hilum, etc., covered by fruit 



coats 



Two cotyledons One cotyledon 



Large embryo Small embryo 



No endosperm Large endosperm 



Plumule fairly large Plumule rather small 



Plumule leaves folded Plumule leaves rolled 



The fruit a pod, with many The fruit a single grain, with 



seeds one seed 



COLLATERAL READING 



Lessons in Botany, Atkinson, pp. 2-208; Natural History of Plants, 

 K. and O., Vol. I, p. 601; Natural History of Plants, Vol. II, p. 450; 

 Lessons with Plants, Bailey, pp. 132-133, 252; Plant Structures, Coulter, 

 pp. 183-184, 210-214; Studies on Plant Life, Atkinson, pp. 158-192; 

 Practical Botany, S. and H., p. 343; Plant Relations, Coulter, pp. 111-115, 

 138-140; Seed Babies (L), Moreley, entire; Elementary Studies in Botany, 

 Coulter, pp. 317-325; Plant Life and Uses, Coulter, pp. 325-353; Experi- 

 ments in Plants, Osterhout, pp. 1-68; Practical Biology, Small wood, 

 pp. 259-267; Cornell Leaflets, Bui. L, pp. 401-414. 



SEED STRUCTURE 

 Definition of seed. 



A plant orsjan whose function is to reproduce the plant, consisting of: 



1. The living miniature plant (embryo). 



2. Stored food. 



3. Protective coverings. 

 Structure of seeds. 



1. Coats. Function, Protection. 

 Testa (outer coat). 



Hilum (scar on testa). Point of attachment for supply of 



nourishment. 



Micropyle (opening). Entrance of pollen, exit of hypocotyl. 

 Tegumen (inner coat). 



