LESSONS IN BOTANY. 



il, nominated t'm ipoilgiol*, tin- fun.-tion of wliich consist* in 

 , and com< , in- it into tho itraoture of the 

 l>hmt. ll.ii'. lii.-i-liiff and primary uuo of the root in tliat of 

 nutrition ; but it also Borvus as a mean* of enabling tho plant to 

 tuko tirm hold of tho earth in wliich 

 it growa. Ik-presentations of various 

 roots are shown in Figs. 5,6, 7, 8, and 9. 



In most coses, the part at which 

 tho stem ends and the root begins ia 

 well defined. It is denominated tho 

 . Although tho general cha- 

 ractoristio of the root is to sock the 

 ground, as the characteristic of the 

 stem is to seek the air, nevertheless 

 stems frequently assume a tendency to 

 become roots, and roots to become 

 atoms. A very remarkable example 

 of tho former tendency is furnished 

 by tho banyan tree, or ficut religiosa, 

 a native of India. This tree has a 

 natural tendency to shoot down pro- 

 longations from ita stem, 

 which, taking root, cover 

 the ground with an arbour- 

 liko growth of most fan- 

 tastic appearance. The 

 opposite tendency is re- 

 cognisable in certain varie- 

 ties of the elm, which shoot 

 up sprouts from the root 

 over largo tracts of ground 

 in the vicinity of the 

 parent trunk, very much 

 to the annoyance of the 

 farmer, whose land is thus 

 considerably damaged. Al- 

 though tho essential cha- 

 racteristic of a stem is to 

 ascend into the air, yet 

 certain forms of stem in 

 some vegetables exist underground ; of this kind are ginger, 

 and the so-called orris-root. Stems of this kind are known 

 in botany by tho appellation of rhizomes (Fig. 3). 



Usually the root is attached by the collar to an ascending 

 stem, from which latter proceed the leaves ; in certain plants, 

 however for instance, the primrose there ia no ascending 

 stem, but an horizontal, underground one (the rhizome) takes 



3. RHIZOME AND BOOT-LEAVES OF 

 THE PRIMROSE. 



say, atole-bearing, which expression require* the previous expla- 

 of the word itole. A ttol*, then, ia a little atom which 

 apringa from the axilla (literally, arm-pit), or point at which 

 the leave* spring from the stem. The strawberry (Fig. 4) affords 

 a common and well-marked illustra- 

 tion of this kind of root. 



A bulb is an underground bod, from 

 the upper part of which the stem 

 arises, and from the lower part of 

 which the root descends (Fig. 7). The 

 oaion furnishes us with a very fniT 

 example. 



Tubers or tubercle* are aijuissliiisi 

 of underground stems, usually eon- 

 taining muchfecularor starchy matter, 

 and studded with eye* or buds. The 

 potato and the dahlia (Fig. 8) furnish 

 oa with very familiar example* of a 

 tuber. 



The Stem may be either annual, bien- 

 nial, or perennial. It ia termed annual 

 when it become* developed 

 in tho spring and die* 

 before the winter, as, for 

 instance, ia the case with 

 wheat ; biennial, when it 

 lives two yean; of thia 

 kind ia the carrot, which 

 during the first year only 

 produces leaves, and hav- 

 ing lived two yean flowers 

 and dies. Perennial stem* 

 are those which live many 

 yean, as is the case with 

 tree* in general As re- 

 gards their hardness, 

 trunks or stems are usually 

 divided into herbaceous 

 (Latin, herba, grass), sub- 

 ligneous, and ligneous 

 (Latin, lignum, wood). Herbaceous stems are those in which 

 woody fibre is almost altogether absent, and which are therefore 

 soft and juicy ; of this kind is the stem of parsley, hemlock, etc. 

 Subligneous stems are those in which woody fibre, although 

 present, does not exist hi tho smaller shoots ; of this kind are 

 sage and rue, the bases of the stems of which are hard and 

 woody, and therefore continue for many years, whereas the 



4. 8TOLOXIFEROC3 BOOT 07 

 TUB STBAWBEBAT. 



5. RADISH. 



SPINDLE-SHAPED ROOT. 



6. DBOPWOBT. 



Kuorrr BOOT. 



7. ONION. BULB WITH 

 FILAMENTOUS SOOT. 



8. DAHLIA. 

 TUBEBOU3 ROOT. 



rnaoe* moor. 



its place, and from this the leaves immediately grow ; such 



leaves are then termed "radical," that is to say, proceeding 



from the root, and the plant itself is said to be acauliferous, 



from the Greek privative o, without, and tho Latin word caulis, 



astern. 



_ Sometimes tho root is said to be " stoloniferons," that is to 



smaller branches and their extremities annually perish, and as 

 often become renewed. 



Shrubs aro ligneous plants, the stems of which throw off an 

 undergrowth of stems and flowers at their base, and which 

 never attain any considerable dimensions. Of this kind, for 

 example, aro rose-trees. 



