374 Plant Physiology 



handled, there are few herbaceous plants of indefinite 

 growth which may not be successfully multiplied in this 

 manner. In general, the growth relations are simple. 

 The propagator employs a small portion of a branch con- 

 taining one or more nodes. These nodes with active or 

 dormant buds are capable of developing shoots. The 

 essential response demanded of the plant is that under 

 conditions favorable for growth it shall be able to develop 

 adventitious roots. Such roots are by no means uncom- 

 mon in nature, and they develop apparently more or less 

 in correlation with the needs of the plant. The extent to 

 which plant parts are able to develop such roots is re- 

 markable. It has been ascertained that cotyledons and 

 leaves are in no small number of cases able to develop 

 these roots as efficiently as stems, and the leaves could, 

 therefore, be employed in propagation if there were also 

 the possibility of bud development. In fact, there are a 

 few types which have the habit of producing buds, and 

 such leaves are made use of in this manner. The leaves 

 of several species of Begonia, notably the varieties of 

 Begonia Rex, also certain forms of Bryophyllum and related 

 plants, are thus employed, as already indicated. 



223. Precautions with cuttings. - - It is evident that 

 branches or shoots used as cuttings require, in general, 

 careful treatment. Twigs or canes in a resting condition 

 may require no special consideration, so that currants, 

 grapes, and other fruits root readily under field or garden 

 conditions. Throughout the South, sugar cane is gener- 

 ally propagated by planting the whole stalks, and also by 

 using the lower parts of stools, - - the rat toons. Shoots 

 in full leaf always require more attention, since the loss of 



