GERMINATION OF BEANS 329 



that the swelling of the seed is the first obvious 

 stage in germination. 



403. Plant beans in moist cotton or sawdust, 

 or lay them in folds of heavy, damp cloth. How 

 far will the sprouting progress? Will the first 

 true leaves develop? In other words, for how long 

 can the plantlet grow upon the nutriment which 

 is stored in the seed? 



404. When the true leaves have begun to de- 

 velop (as in Figs. 348 and 349), carefully lift the 

 plant, with the soil which is attached, and then, 

 in a basin, wash away the earth until the roots 

 are white and clean. Then, by the aid of a lens 

 or by holding the roots to the light, see the cov- 

 ering of very fine hairs upon the roots. It is 

 these little organs which hold most of the earth 

 on the roots when the plant is carefully pulled 

 up. They are the root -hairs, and they are active 

 agents in absorbing food. 



404a. Several profitable lessons may be made in the study of 

 the root-hairs of whatever seedling plants may be at hand in 

 gardens or elsewhere . How soon after germination do they appear ? 

 Do they persist as the root becomes old, or are they shed upon 

 the older parts ? Do full-grown or large plants have i-oot-hairs ? 

 Look for them on the very youngest parts of the roots. When 

 seeds are germinated as recommended in 392 and 403, the root- 

 hairs are much more readily seen. 



405. We know that roots go downwards and 

 stems go upwards. How soon is this difference 



