432 THE PRINCIPLES OF FLORICULTURE 



varieties may be planted three or four feet apart ; pom- 

 pons and Tom Thumbs require only two or two and 

 one-half feet. The plants should be cultivated often and 

 kept free from weeds. In times of drought, continuous 

 cultivation should be given to keep the soil stirred. Be- 

 fore the plants bloom, however, all deep cultivation should 

 cease, and, if needed, a mulch may be given. The use of 

 too much nitrogen should be avoided, as dahlias naturally 

 run to foliage. If growth is not satisfactory, liquid 

 manure may be applied. A liberal application of bone- 

 meal just before the plants bloom tends to improve the 

 keeping qualities. Some growers apply nitrate of soda 

 and bone-meal broadcast, using four parts bone-meal and 

 one part nitrate of soda. A small handful will cover an 

 area about one and one-half feet square. 



726. Gladiolus, botanical classification. Order, Irida- 

 cese ; genus, Gladiolus (from Latin gladius, meaning sword, 

 referring to the shape of the leaf) ; species : there are at 

 least 135 species, although but about a dozen have been 

 thought worthy of floricultural hybridization. The best 

 method of showing the species of importance is to present 

 a diagrammatic scheme of the probable evolution of the 

 various types now in the trade : 



G. oppositiflorus X G. psittacinus or G. cardinalis. 

 G. gandavensis X G. purpureo-auratus 



G. gandavensis X G. Saundersi X G. Lemoinei 



i i 



Leichtlin products G. nanceianus X G. cruentus. 

 (G. Childsii). 



Variety Princeps. 



