304 THE PRINCIPLES OF FLORICULTURE 



ough watering. Later, only enough water is given to 

 keep the plants from wilting, for antirrhinums will not 

 grow in a wet soil. Their natural habitat out of doors 

 is on dry banks or even in crevices in rocks. Special 

 care in watering should be taken on dark days in mid- 

 winter. They should never be syringed in winter, but 

 on bright days in spring, a thorough syringing will be 

 beneficial. 



446. Temperature. A night temperature from 48 to 

 52 suits the antirrhinum. If the temperature oc- 

 casionally falls to 45, the plants will not be injured. The 

 day temperature should not go above 70. 



447. Feeding. After the plants are once established 

 in the beds, they require very little feeding. If the soil 

 is light and there seems a lack of plant food, a moderate 

 application of bone-meal may be given. This will cause 

 the plants to produce stronger stems. No quick-acting 

 fertilizer, such as nitrate of soda, should be used, but 

 small amounts of liquid cow manure may be given oc- 

 casionally. 



448. Insect pests. Antirrhinums are troubled by 

 few insects. They may be attacked by the green and 

 black aphis, and this should be controlled by fumigation 

 with some extract of nicotine. The leaf-roller is some- 

 times troublesome, and must be hand picked, for applica- 

 tions of arsenate of lead discolor the foliage. The plants' 

 are also easily injured by fumigation with hydrocyanic 

 acid gas. 



WALLFLOWERS 



449. Botanical classification. Order, Cruciferae ; 

 genus, Cheiranthus (derivation in dispute, but probably 

 from the Greek for hand and flower) ; species, Cheiri. 



