CRUCIFER^. 335 



table, these basal leaves are tied up about the fleshy, white 

 head to prevent its browning by the sun. 



A distinction is made between cauliflower and broccoli. 

 The latter requires a longer time to mature than cauliflower; 

 furthermore, the heads are smaller and the leaves broader, 

 narrower, stiffer and more numerous. 



Cauliflower and broccoli are both cool-season crops. 



BRASSICA RAPA (Turnip) 



Description. — The common turnip is a biennial. The 

 first year a swollen and fleshy tap root is formed. However, 

 the "turnip" is combined primary root and hypocotyl. The 

 upper portion to which the leaves are attached is stem, while 

 the lower portion to which secondary roots are attached is 

 root. 



The leaves that arise from the "turnip" the first season are 

 in the form of a rosette. They are oblong to oval, some- 

 times entire, serrate, or the later ones pinnate or pinnatifid. 

 First-year leaves are grass-green and rough-hairy. The sec- 

 ond season, a stem i to 3 feet tall is sent up from the ter- 

 minal bud in the center of the rosette of leaves, which bears 

 alternate, clasping, lanceolate or oblong, entire or dentate, 

 smooth leaves. The flower stem is branching. The inflores- 

 cence is a raceme. The flowers are bright yellow, about 3^ 

 inch in diameter and of the characteristic mustard type. 

 The fruit is ij^ to 2 inches long, cylindrical, and tipped by a 

 short beak. The seeds are reddish brown in color, spherical, 

 and number 15 to 25 in each silique. 



Geographical. — The turnip seems to have originated in Europe or Western 

 Asia. By cultivation, it has spread into all temperate regions. The cul- 

 tivated sorts are grown as cool-season crops. 



Types of Turnips. — There are numerous varieties of turnips, 

 varying chiefly as to shape and color of "root" (Fig. 140). 



