24 Principles of Plant Culture. 



corn, wheat and many other seeds, the seed- case is of 

 such a nature that it absorbs and transmits water readily. 

 In certain seeds, however, as of the honey locust, canna, 

 thorn apple etc., especially if they have been allowed 

 to become dry, the seed-case does not readily transmit 

 water at growing temperatures. Such seeds may lie for 

 weeks, and even months, in tepid water without swell- 

 ing, but when the water is heated to a certain degree, 

 they swell promptly, a fact often turned to account by 

 nurserymen (36). We cannot always judge by the ap- 

 pearance of a seed-case whether it will transmit water 

 readily or not. 



SECTION II. GERMINATION 



28. What is Germination? If we place a few viable* 

 grains of Indian corn between the moist cloths of a seed- 

 tester (Fig. 5), cover with the glass and place in a warm 

 room, we shall observe if we examine the corn fre- 

 quently, that a change, aside from the swelling, will soon 

 take place in at least a part of the grains. The seed- 

 case will be burst by the pressure of a tiny white shoot 

 from beneath. We say that such grains have sprouted 

 or have commenced to germinate (ger'-mi-nate), i. e., 

 have taken the first visible step toward developing into 

 a plant. 



We have seen that the mature seed contains proto- 

 plasm in its dormant condition (13). At a suitable tem- 

 perature, the protoplasm, on the absorption of water, re- 

 carp, testa, etc., according to their exact office in the make-up of the plant. 

 To avoid explaining the technicalities of a complex subject, it seems pre- 

 ferable to adopt a term that will include the various words used in botany 

 to designate the outer coverings of seeds. 



* A viable (vi'-a-ble) seed is one that is capable of germination. Not 

 all seeds are viable (165). 



