NITROGEN-CONSUMING PLANTS 229 



LEAP CROPS 



Cabbage (Bras sic a oleracea var. capitata). The leaves of the wild 

 plant from the seashore of southwestern Europe are enlarged and massed 

 together to form a head. 



Kale and Collard (Brassica oleracea var. viridis). Collards are 

 much grown in the south particularly Georgia. The stem is branched 

 and leafy with broad leaves. 



Brussels Sprouts (Brassica oleracea var. gemmifera}. The axillary 

 buds of this variety of cabbage plant have increased in number along the 

 stem and form small rounded heads, or "sprouts." 



Peh-ts'ai (Brassica chinensis). The Chinese cabbage attains its 

 perfection in the colder parts of China. It has recently been introduced 

 into cultivation in the United States. 



Lettuce (Lactuca saliva). There are several varieties of lettuce, 

 which are cultivated for their leaves, which are used for salad. The 

 cos lettuce and head lettuce are the most common. 



Endive (Cichorium endivia). The leaves of this plant are used as 

 greens, as also those of the closely related succory (C. intybus). 



Celery (Apium graveolens). The blanched, basal sheath of the leaves 

 and the petioles represent the market celery. The plant was originally 

 cultivated in Europe. 



Parsley (Apium petroselinum). The leaves, which are gathered for 

 use as a pot herb, are plain, or curled. 



Rhubarb (Rheum rhaponticum) . The use of the succulent leaf stalks 

 for stewing and for tarts is widespread. 



Dasheen (see under root crops).' 



Spinach (Spinacia oleracea). The leaves of this are much in demand 

 ior greens. It is a native of southwestern Asia and in China is called 

 po-ts''ai. 



New Zealand Spinach (Tetragonia expansa). The tender leaves and 

 tips of the stem are used for greens. 



Tea (Camellia Thea). The young leaves of this shrub are gathered 

 and dried for export from the various warm temperate countries where tea 

 is grown as a commercial crop. The industry is an enormous one in China. 



Mate (Ilex paraguayensis). The leaves of this shrub are used as a 

 popular beverage in several South American countries. 



