47© BOTANY OF CROP PLANTS 



The Names Derived from "Linum." — This family contains 

 but one important genus, Linum. The name Linum is the 

 latin for flax. The word "linen" means made from flax or 

 of flax. It is from these and other similar foreign names 

 that we get our common words linen, lint, linseed, and line. 



Geographical, and Environmental Relations. — The family 

 has about 135 species, which are widely distributed over the 

 world. The important commercial species is L. usitatissi- 

 mum. All cultivated flax varieties in this country are 

 treated as belonging to this one species. 



Flax is raised under a wide variety of cUmatic conditions 

 and soils. In regions with low rainfall, the crop is of little 

 value for fiber, and hence is grown chiefly for its seed. A 

 fair quaUty of fiber flax is produced in certain sections of the 

 United States where the rainfall is 25 to 30 inches. The 

 water requirement of flax is higher than that of any of the 

 cereals, being about three times that of millet and sorghum. 



LINUM USITATISSIMUM (Common Flax) 



Habit, Root. — Common flax is an upright herb which 

 under cultivation grows to a height of from i to 4 feet 

 (Fig. 199). 



It is a dainty surface feeder with a small root system; this 

 consists of a slender tap ro9t sparingly supplied with slender 

 branches in the first 12 to 18 inches of soil. The tap root 

 runs downward vertically to a depth of 3 to 4 feet in some 

 cases. No network of roots is formed near the surface of 

 the soil. Long-stemmed flax as compared with other varie- 

 ties appears to have a weaker root system and less root 

 penetration. Deep planting is adverse to root development 

 of flax. 



Stem. — The stem is simple, erect, and branching in the 

 upper part, rarely at the base. As it matures, it becomes 



