48 BIOLOGY FOR BEGINNERS 



Stages in germination: 



1. Emergence from seed coats. 



Adaptations, Micropyle, Cap on hypocotyl. 



2. Penetration of soil. 



Adaptations. 



By arching method caused by 



(1) Soil pressure (bean) . 



(2) Cotyledon pressure (pea). 



By direct piercing. 



(1) By rolled plumule with a sheath as in corn. 



3. Obtaining nourishment. 



(1) From stored food in cotyledons. 



(2) " " " endosperm. 



(3) Obtained directly by leaf-like cotyledons (squash), roots from 



hypocotyl, development of plumule leaves. 



NOTE. If the hypocotyl does not lengthen upward, the cotyledons 

 must remain below ground; if it does lengthen the cotyledons "come up." 

 Cotyledons may store food below ground or above; they may become 

 true leaves, or merely act as absorbing organs. (Give an example of each.) 



Experiments to show: 



1. The kind of food stuffs stored in seeds. 



2. The necessity for this stored food. 



3. The need of digestion before it can be used. 



4. The necessity of air, moisture, and warmth for germination. 



5. That growing seedlings produce heat and carbon dioxide (that is, 

 that they breathe). 



COLLATERAL READING 



Natural History of Plants, Kerner and Oliver, Vol. I, p. 599; Vol. I 

 (2), pp. 598-623; Vol. II (1), pp. 420-427; Lessons with Plants, Bailey, 

 pp. 336-341; Lessons in Botany, Atkinson, pp. 210-216; Studies in Plant 

 Life, Atkinson, pp. 1-6; Seeds and Seedlings, Lubbock, Vol. I, pp. 4-77; 

 Textbook in Botany, Gray, pp. 9-27, 305-314; The Teaching Botanist, 

 Ganong, pp. 161-190; The World's Farm, Gaye, pp. 277-299. 



Lessons with Plants, Bailey, pp. 316-335; Plant Relations, Coulter, 

 pp. 138-141; Botany for Schools, Atkinson, pp. 1-25; Elementary Botany, 

 Atkinson, pp. 307-313; Experiments in Plants, Osterhout, pp. 69-86; 

 Plants and Their Children, Dana, pp. 75-98. 



