MICHIG AND EXPERIMENT STATION BULLETINS 



.'U7 



Fig. 9. Young seedliog 



the bean. The small bud between the seed-leaves of 

 the pea does not come straight out, point foremost, but 

 doubles up and pushes hard with its back bursting the 

 seed-coat, leaving a small hole, and then the arch 

 keeps moving or pushing its way out of the soil. 



Why do you suppose peas and beans in growing out 

 of the soil, come out double in form of a bow, instead P°^J^l/theTeedYeav'?3''r7- 

 of sending the tip of the seed-leaves or the stem mainingbsiow. 



»\ straight out? Very likely this is the correct explana- 



^^ tion. It enables the young seedling the better to 



break through a hard soil without injury to the tender 

 plant. 



As the young plant grows older the seed-leaves be- 

 come smaller and withered, as their substance is 

 carried out to nourish young roots, stems and tender 

 Fig 10 The first tender leaves. Half an inch or more above the seed-leaves 

 bud of the pea backiug of the pea appears a single three-pointed scale, and 

 8^d-ieav™8. '^^'^^^^ * above this and part way around the stem is another 

 scale rather larger and more or less green. 



In this, the second scale, there are two pieces facing 

 and matching each other as they press against the stem, 

 and between them curling outward is a small, slender, 

 green object. At the third step up the stem, are seen 

 two rather large, flat and green objects, between which 

 spread out from the main stalk a small stem about an 

 inch long with a^groove on the upper side, and at the 

 end of this are two more flat green objects with a little, 

 slender tendril between them. All of the first or lowest 

 three-pointed scale on the main stem represents or really 

 IS a small leaf, and the same is true of the second three- 

 pointed scale; likewise of all that appears in the third 

 place as above described. Such a leaf is called com- 

 pound, as it is composed of more than one piece. If the 

 pupils were to pursue the subject further, they would 

 see some of the other leaves containing a larger number 

 of parts, and the little, slender curl become longer and 

 branching and ready to curl about and cling to any 

 straws and sticks that happen to be within reach. 



Kept on moist soil, sand or fine gravel, peas were seen 



Fig. 11. Seedling pea : to Send out a root, which curved about more or less, usually 



feafshowi^ng'asiiiairw keeping its tip to the ground. In some cases this tip 



drii.^c. third leaf and a found its wav iuto some little crevic€ and kept on its way 



fourth ]U8t appearing to j u j. • ii, j.1. L^ c -ii 



the left. downward, but in other cases on the smooth surface with 



nothing to bear down and hold it, the peas tilted over, and again the root- 

 tip turned toward the soil. After continuing and wandering about perhaps 

 for two inches' with a curve high in the air, several side roots branched out, 

 grew to the soil and came to the rescue. If kept well moistened continu- 

 ally, the main root and its smaller branches beginning a little way back of 

 the tips, were seen to have all over the surface for half an inch, the appear- 

 ance of white velvet caused by immense numbers of root-hairs. 



