374 THE STRUCTURE OF ECONOMIC PLANTS 



The Flower. — The flowers are terminal and blue or white in 

 commercial varieties, the more common blue-flowered types fre- 

 quently having a streak of dark blue in the throat of the corolla. 

 The white-blossomed types require 7 to 10 days longer for bloom- 

 ing and are grown very little in 

 the United States since they pro- 

 duce a relatively coarse fiber. 

 The flowers are hypogynous and 

 tetracyclic with five sepals, five 

 petals, five stamens, and a com- 

 pound pistil of five carpels in a 

 radially symmetrical arrange- 

 ment. (Fig. 190, A-F.') The 

 persistent sepals are much im- 

 bricated in the bud and are un- 

 equal in size, the two outermost 

 ones being smaller than the other 

 three, the third sepal intermedi- 

 ate in size, and the two innermost 

 ones the largest. The blade of 

 the sepal is oval, acuminate and 

 glabrous, except for the margins 

 which may be scarious, and the 

 tip is ciliated. The ephemeral 

 petals are wedge-shaped, about 

 twice the length of the sepals, 

 and their margins overlap one 

 another in either a right- or left- 

 handed spiral. In most instances, 

 the flowers open in early morning 

 and the petals begin to fall at 

 about nine or ten o'clock when 

 the sun becomes hot; but, if it 

 is cloudy, the corolla may remain in place throughout the day. 



The androecium is slightly monodelphous at the base; and, 

 on the margin of the undiverged staminal ring, there are usually 

 five tooth-like staminodia which alternate with the filaments of 

 the five fertile stamens. These are small processes, not exceeding 

 a millimeter in length; but Tammes (xx) has reported cases in 

 which varying degrees of development were found, some even 



Fig. 189. — Habit of flax plant showing 

 character of stem and inflorescence. 

 (Photograph by Copson.) 



