POTTED FLOWERING PLANTS 351 



POINSETTIAS 



538. Botanical classification. Order, Euphorbiacese ; 

 genus, Euphorbia (classical name) ; species, pulcherrima. 



539. Botanical characters. Poinsettias are shrub- 

 like plants with milky juice. The foliage is attractive. 

 The flowers are yellow and inconspicuous, but the flower- 

 cluster is surrounded by an involucral crown of intense 

 crimson leaves. 



Habitat. Tropical Mexico and Central America. 



540. Commercial importance. Poinsettias are dis- 

 tinctly Christmas plants, and the demand for them is 

 limited to a short season. They are grown in large quan- 

 tities, and are used for cut-flow^ers and for potted-plants. 

 Small plants are especially pleasing when used with ferns 

 or other foliage plants. 



541. Propagation. Poinsettias are propagated from 

 cuttings which are taken from April until the middle of 

 August. When the plants are through flowering, the first 

 of January, the stock plants are selected, and placed under 

 the benches for at least ten weeks. Here they are allowed 

 to become dried, but the wood should never shrivel. They 

 should be kept in a temperature of 50 to 60. About the 

 middle of April, the old soil should be shaken off, and the 

 plants potted in new, rich soil. They are then cut back 

 considerably and placed on a sunny bench where they will 

 get some bottom heat. New growth will start almost 

 immediately, and this furnishes the material for cuttings. 



542. Culture. As soon as the cuttings are rooted, 

 they should be potted carefully so that the roots are 

 not injured. They break easily, and if broken, the 

 vitality of the plants is weakened. A good, fibrous loam, 

 to which has been added about one-fourth the bulk 



