LK8SON 5.] MOKl'llOLOCY OK ROOTS. "29 



for tlic yoniic; J^tinlcnt to learn them by rote. Tlio student slicmld 

 rather consider the eonneetioii between one Ibnii and anotlier ; and 

 notice liow the one simple plan of the plant, as it has alrea<ly been 

 illustrated, is worked out in the greatest variety of ways, through the 

 manifold diversity of forms which each of its three organs of vege- 

 tation — root, stem, and leaf — is made to assume. 



G3. This wc are now ready to do. That is, having obtained a 

 g neral idea of vegetation, by tracing the plant from the seed and 

 the bud into the herb, shrub, or tree, we proceed to contemplate the 

 princi|)al forms under which these three oigans occur in diHi-rent 

 plants, or in different parts of the same plant ; or, in other words, to 

 stuily the moiylioloyij of the root, stem, and leaves. 



64. Of these three organs, the root is the simplest and the lea^t 

 varied in its modifications. Still it exhibits some widely di(l"erent 

 kinds. Going back to the beginning, we commence with 



G5. The sim|)Ic PrilUtiry Root, which most plants send down from 

 the root-end of the embryo as it grows from the seed; as we hav 

 seen in the Maple (Fig 5-7), Morn ing-G lory (Fig. 8 and 28), 

 Beech (Fig. 14, 15), Oak and IJuckeye (Fig. 22-24), &c. This, 

 if it goes on to grow, makes a main or tap root, from which fide- 

 branches here and there proceed. Some plants keep this mair 'root 

 throughout their whole life, and send off only small side bra' rhes ; 

 as in the Carrot (Fig. 58) and Radish (Fig. 59) : and in some trees, 

 like the Oak, it takes the lead of the side-branches for many years, 

 unless accidentally injured, Jis a strong tap-root. But commonly 

 the main root divides off very soon, and is lost in the branches. 

 We have already seen, also, that there may be at the beginning 



OG. Mi;lti|)Ic Primary Roots. We have noticed them in tiie Pump- 

 kin (Fig. lU), in the Pea (Fig. 20), and in Indian Corn (Fig. 42). 

 That is, st;veral roots have started all at once, or nearly so, from the 

 seedling st(,'m, and formed a bundle or cluster (a fascicled root, as 

 it is called), in place of one main root. The Bean, as we observe 

 in Fig. 18, begins with a main root , l)ut some of its branches soon 

 ov<'rtake it, and a clM<ter of roots is (()rrne(l. 



G7. Absorplioii of Moisture by Roots. Tin- br.Miciies of roots as they 



grow coimnoidy branch again and again, into smaller roots or rootlets ; 

 in this way very much increjw^ing the surface liy which the plant 

 connects its(df with the earth, and absorbs moisture from it. 'I'he 

 wholf! surface of tin; root al)sorbs, so long as it is fresh and new ; 

 and the newer the roots and rootlets are, the more freely do they 

 3* 



