THE FLOWER 



GROWER'S 



GUIDE. 



Tlie most active and absorbent portions of roots are the parts just behind the 

 growing points or the portions usually thick-set with root-hairs (see Fig. 7). Although 

 most I'oots are buried in the ground, we must never forget that roots must breathe, and 

 that thej^ will soon die in close stagnant soils. Eoots may be choked or drowned in 

 soils that are not permeable to the air, and hence the necessity of drainage in flower- 

 pots and the free passage of water through garden soil ; then air follows the water under 

 atmospheric pressure of som.e 2,U00 lbs. to each square superficial foot. 



In some natural orders of plants, such as in the orchids, bromeliads, also many 

 ferns and lycopods, in aroids and many tropical creepers, we find roots especially 

 adapted for partial exposure to light and air. If you look carefully at many orchids, 



such as cattleyas, vandas, phalsenopsis, and dendro- 

 bium, you Avill find roots of two kinds, viz., those 

 embedded in the pot or basket of compost which 

 are generally etiolated or blanched, and mainly 

 serve for firm anchorage and the absorption of 

 water, and the aerial roots Avhich are silvery white 

 with green growing points to them (Fig. 8). These 

 last absorb not only water, but ammonia and car- 

 bonic dioxide, having, in fact, a partial leaf function 

 as well as a partial root function. 



Stems. ' ' - 

 These are, roughly speaking, of two kinds, 

 namely, those usually produced above the ground, 

 and those formed for special purposes below the 

 ground level, AVhen stems are subdivided, the 

 divisions above ground are usually called branches, 

 and branches arc developed buds that may form in the axils of all leaves. Some- 

 times axillary buds do not elongate, but become fleshy, as in the case when bulblets or 

 tubers are formed on the stems of some lilies and other plants. 



Stems may be woody or herbaceous, and either simple or much branched. Tall- 

 groAving, woody stems are protective; they also act as conductors of sap or earth salts 

 in solution, as it is attracted from the roots towards the leaves. Stems also act as 

 receptacles for the conservation of the formed or elaborated materials, such as starch, 



