310 THE NURSERY LIST. 



cellar. The next spring they are planted out in beds, 

 and during the following summer and winter they are 

 given some protection from sun and cold. Yews and 

 arbor-vitaes are handled in the same way. 



Retinosporas are often grafted upon retinospora or com- 

 mon arbor-vitae stocks. This operation is usually per- 

 formed upon potted plants in winter by the veneer method. 



Rhamnus, including Frangula (Buckthorn). Rhamnacece. 



The hardy kinds may be increased by means of seeds 

 or by layers. The stove and greenhouse species may be 

 multiplied by cuttings of growing parts. Seeds should 

 be stratified. 



Rheum (Rhubarb, Pie-plant, Wine-plant). Polygonacece. 



. Increased by seeds and by division. Each division 

 should contain at least one bud on the crown. Seeds 

 may be sown where the plants are to stand, but will not 

 reproduce the varieties, and three years are required for 

 the plants to mature. 



Rhipsalis, including Lepismium, Pfeiffera. Cactacece. 



Cuttings, after having been dried for a few days, should 

 be inserted in coarse gravel or sand. See Cactus. 



Rhodanthe. See Helipterum. 



Rhododendron, Azalea (Rose-Bay). Ericacecs. 



Seeds are largely employed, but they are small and 

 light, and must be carefully handed. They are sown in 

 spring in pans or boxes in a soil 01 sandy peat, care being 

 taken to cover them very lightly and not to dislodge them 

 when applying water. They are handled in coldframes 

 or in a cool house, and the young plants must be shaded. 

 The plants are commonly allowed to remain a year in the 

 boxes. Low-growing plants are often layered. Cuttings 

 of growing wood, cut to a heel, are sometimes employed, 

 being made in summer and handled in a frame, but the 

 percentage of rooted plants will often be small. Rhodo- 

 dendrons are extensively grafted, the veneer method be- 

 ing most used. The operation is performed upon potted 

 plants in late summer or early fall, or sometimes in a cool 

 house in early spring. Most of the leaves are allowed to 

 remain upon the cion. The plants are then placed in 

 densely shaded cool frames (Fig. 47), and are nearly cov- 

 ered with sphagnum. Various stocks are employed, but 

 for severe climates the hardy species, like R. Catazvbiense 



