256 BOTANY OF CROP PLANTS 



is a very hardy, low, bushy tree with small fruit which varies 

 in color from white to red and almost black. It is an im- 

 portant wind-break and shelter-belt tree in the Great Plains. 

 Teas' weeping mulberry is an ornamental variety of the 

 Russian. Morus alba var. venosa (M. nervosa) is an orna- 

 mental curiosity bearing jagged leaves with white, prominent 

 veins. 



Morus muUicaulis {M. alba var. muUicaulis) was intro- 

 duced into America in 1826 and, for a while, gave a great 

 impetus to the attempts to grow silkworms. It is a small 

 tree with rough, long-pointed leaves. 



The chief horticultural varieties of the white mulberry are : 

 New American, Trowbridge, Thorburn and Downing. The 

 Downing is supposed to be a variety of M. muUicaulis. 

 However, the so-called Downing of most nurserymen is the 

 New American. 



Early Attempts in the United States to Grow Silk.— The 

 white mulberry has been cultivated from the earhest times, 

 chiefly for feeding the silkworm. In 1621, mulberries were 

 introduced into Virginia by the London Company with a view 

 of establishing the silk industry in the New World. Early 

 attempts to grow silk were made not only in Virginia but in 

 Carolina, Georgia and Connecticut. After the Revolution, 

 early in the 19th century, silk culture was again agitated. 

 There existed what has been called " The Morus muUicaulis 

 mania." This species was introduced into America in 1826, 

 and since it was thought to be the source of the renowned 

 Chinese silk, soon gained wide fame here. The "craze" 

 died down in about 1836, and since that time, there has been 

 little effort to grow silk in North America upon a commercial 

 scale. 



Uses. — ^As has been said, the white mulberry is the one 

 upon which silkworms are raised. In the Old World the 



