404 BOTANY AND PHARMACOGNOSY. 



It is well known that when growth is very rapid the plant will 

 produce few or no flowers, whereas if growth is slower the pro- 

 duction of flowers and seed will be increased. So in the case of 

 some of the medicinal plants it is probable that the yield of active 

 principles would be less in a very vigorous plant than in one less 

 thrifty. The conditions must, therefore, be studied in relation 

 to the object to be attained. 



In undertaking the cultivation of native medicinal plants they 

 should first be studied in their natural surroundings until a 

 knowledge is gained of the peculiar requirements and habits of 

 each, including the composition and physical condition of the 

 soil, the climatic conditions, their relation to other plants, etc. 

 It should at the same time be borne in mind that most plants 

 can in time adapt themselves to surroundings differing from 

 those of their original habitat. Still, notwithstanding this gen- 

 eral law of adaptation, in order to be sure of results we must 

 take into consideration the particular conditions under which a 

 given species will thrive best, or yield the largest percentage of 

 active principles. For example, some plants appear to prefer a 

 dry soil, as Sassafras officinale; others, a damp location, as J^cra- 

 trnm viride ; some, a rich soil, as Asariim canadense, while still 

 others grow in waste places and on ballast, as Matricaria Chamo- 

 milla. Some prefer shade, as Ariscema triphyllnm, and others ex- 

 posure to direct sunlight, as Datura Stramonium. Among the 

 other factors which must also be taken into consideration is that 

 of altitude, some plants appearing to thrive best high up on hills 

 and mountains, while others are found in the lowlands and 

 marshes. The question of latitude must also be considered owing 

 to the extremes in our country in this particular. 



PROPAGATION. The methods of propagation used in the 

 cultivation of other useful plants apply also to medicinal plants. 

 These include propagation from seeds, from cuttings, and from 

 grafts. A CUTTING is a severed portion of a plant having one or 

 more nodes or buds. A graft is a severed twig or branch which 

 is embedded in a branch of another plant in such a way that the 

 cambiums or growing regions of the two branches are brought 

 into such intimate contact that they fuse or grow together. This 

 method is largely followed in fruit culture, the branch of a more 



