232 NATURAL HISTORY. 



purple flowers ; ten stamens, five pistils ; seeds small, 

 black and angular. This handsome weed grows in 

 wheat fields often two or three feet high ; is a great 

 nuisance to farmers, as it makes the flour blue and the 

 bread bitter. 2.* 



TWELFTH FAMILY. LINAGES. FLAXWORTS. Class 

 5, L. 



Flax (Linum usitatissimum) has small, lanceolate leaves, 

 of a beautiful green color ; stem upright, flowers large 

 and blue ; flower petals oval shaped, somewhat twisted. 

 This useful plant grows wild or among grain in the south 

 of Europe, but was largely cultivated in the north, until 

 nearly superseded by cotton. The flowers close in the 

 evening ; the capsules are five-celled and globose ; seeds 

 mucilaginous and oily, are employed in medicine, and 

 yield the Unseed oil so extensively used in mixing paint, 

 printer's ink, varnishes, etc. The fibers of the bark, 

 very strong and fine, are manufactured into linen. O- 

 There are inferior species, such as Linum Riyidum, 

 Linum Virginianum, flowers yellow, and Linum Diffu- 

 sum, found on wet prairies. 



THIRTEENTH FAMILY. MALVACEAE. (J., L., C. 16.) 

 This genus is composed of plants or shrubs. A some- 

 what important class of plants, forming about one fiftieth 

 of all the flowering plants of tropical valleys. In the 

 Northern States they are all herbs. The most important 

 product of the order is Cotton. The fruit is composed 

 of twelve carpels arranged circularly around the calyx ; 

 the children sportively call them cheeses, a name very 

 naturally suggested by their form. The Hibiscus and 



* The Scarlet Lychnis, Ragged Robin, Chinese Lychnis, found 

 both in Europe auJ the Uuited States, belong to this family. 



