No. 493] THE PIIEXOGAJIOUS PARASITES 



13 



orated condition. The supply of inorganic material 

 is obtained by normal plants partly in a soluble and partly 

 in a gaseous condition, the former being contained in the 

 food-sap which the roots derive from the soil, and the 

 latter in the atmosphere which surrounds the plant. The 

 function of the root requires a constant accession of mois- 

 ture, and that function is vital with relation to the other 

 functions of the plant presently to be referred to. The 

 action of sunlight is indispensable in the condensation and 

 elaboration of those inorganic materials into new organic 

 substance. An essential step in that elaboration of new 

 material is the production of chlorophyl, which takes place 

 partly in the bark of the growing branches, but mainly in 

 the parenchyma of the leaves. Fully developed green 

 leaves are therefore among the chief organs of normal 

 phenogams, and their absence from the greater part of 

 phenogamous parasites is due to the inability of those 

 plants to produce chlorophyl. It is for these reasons that 

 chlorophyl is so frequently mentioned in the following 

 paragraphs. 



The reproduction of normal phenogams is by two meth- 

 ods, namely, parturital 1 and blastenial. 2 These methods 



frequently necessary to refer to them. The firstMs the 

 conjugative method and provides for the hereditary trans- 

 mission of specific and other systematic characters, the 

 geographical distribution of species and the multiplica- 

 tion of individual plants. It is periodically cyclic, the 

 maturation of the seed ending one cycle and the germina- 

 tion of its embryo beginning another. The second is the 

 autogenous method and pertains to the growth and pres- 

 ervation of the individual plant. Its operation is phys- 

 ically continuous during the whole life of the plant, and 

 every bud of the plant is connected with all the other 

 buds by living somatic cells. The horticultural processes 

 of budding and grafting consist of transferring blastemal 



1 Parturio, to bring forth young. 

 ' ' asexual. »» * « vegetative.. ' ' etc., which are often used by writers. 



