28 



Elementary Work in Botany. 



food from the air with which to feed the tender plumule, until 

 it also is strong enough to face Jack Frost. If you carefully 

 examine these seeds in various stages of their growth, you 

 will learn that the plumule is at the bottom of a short tube 

 formed by the united petioles of the cotyledons. 



EXERCISE is. 



[Read and discuss in the class.] 



The seedlings of the Western or Brown's peony dodge 

 Jack Frost in a peculiar way. The small embryo feeds for 

 some time upon its abundant store of endosperm before it 



bursts the hard coat. The first 

 growth is made by the stems of 

 the cotyledons, which push the 

 caulicle and its terminal bud, the 

 plumule, fairly out of the shell. 

 This movement shows plainly that 

 the embryo does not intend to 

 carry its store of food above 

 ground, as is the custom of castor- 

 beans. Nor does it risk decapita- 

 tion at the hands of Jack Frost. 

 Neither the hypocotyl nor the epi- 

 cotyl grows, but a solitary leaf is 

 sent up into the air by the growth 

 of its stem, which, with the unde- 

 veloped bud-like blade, looks exactly as we would expect 

 the entire plumule to look. This leaf grows for several 



Fig. 22. Germination of Brown's 

 Peony, a. Section of the seed show- 

 ing the minute embryo at the right 

 embedded in the endosperm, b. The 

 embryo with the cotyledons sepa- 

 rated. <:. The seed germinating, d. 

 The same with the coat removed, 

 showing the growth of the cotyle- 

 dons e. Stem of the first leaf. /. 

 The first leaf older and the blade ex- 

 panded. 



