CULTIVATION OF MEDICINAL PLANTS. 405 



desirable fruit tree being frequently engrafted on one which pro- 

 duces an inferior grade of fruit ; besides, the process consumes 

 much less time than would be required for a fruit-bearing tree 

 to develop from seed. 



Most annuals and biennials are propagated from seeds. Con- 

 siderable care is necessary in the buying of seeds in order to 

 obtain those that will germinate and are true to name. Fre- 

 quently some of the seeds are immature, and in some cases many 

 of them are sterile, as those of Eucalyptus (Fig. 258, H). This 

 latter fact may explain why it is so difficult to grow the eucalypts 

 from seeds. In some instances the seeds may be sown where 

 the plants are to be grown, but probably in most cases it would 

 be better to germinate them under glass or in seed boxes and 

 then transplant the young, plants when the conditions are most 

 favorable. It may be pointed out that there is much variation 

 in seeds in regard to the length of time required for germination. 

 This applies not only to seeds of different species, but even to 

 seeds of the same plant. With many plants, as corn, wheat, beet 

 and others, it has been found that by selecting the best seeds or 

 those produced by plants having some specially desirable quality, 

 as a large percentage of oils, proteins, or sugar, and repeating the 

 selection from year to year, decided improvements have been 

 brought about and maintained. It is reported that in the cinchona 

 plantations in Java methods of selection have largely superseded 

 the system of "mossing" (p. 518) for increasing the alkaloidal 

 percentage. 



Cuttings are extensively employed in the propagation of 

 plants, particularly by florists. They are derived either from 

 over-ground shoots, as in carnation, rose, geranium and coleus, 

 or, where the plant produces root-stocks or rhizomes, they are 

 made from these rather than from the over-ground shoots. Not 

 all plants can be propagated equally well from cuttings. Some 

 plants are readily propagated in this way, as the willows, the 

 twigs of which when they fall off or are broken off frequently 

 take root in the moist soil. Other plants, like the oak, are very 

 difficult to grow from cuttings. In propagating plants from rhi- 

 zomes the latter are cut into pieces, each of which has one or two 

 buds, and these pieces are planted. Among the medicinal plants 



