654 BOTANY OF THE LIVING PLANT 



axillary buds specialised for storage and propagation, are deficient in 

 fats, and contain little proteins. More than four-fifths of the organic 

 substance is in the form of starch. Hence potatoes are used with 

 meat and fats to make a well-balanced meal. Some of the protein is 

 in the form of cubical crystalloids, located near to the corky rind, and 

 thus liable to be removed by peeling the potato (Fig. 82, p. 124). 



The Beet {Beta vulgaris and B. maritima, L. Chenopodiaceae) grows 

 wild on sandy shores in the Mediterranean region, extending northwards 

 to our own coasts. Its originally slender root became fleshy from the 

 effects of soil and cultivation, and Vilmorin has shown that it is one of 

 the plants most easily improved by selection. It has been cultivated 

 since before the Christian era. The fleshy root, characterised by 

 repeated cycles of separate vascular strands, as seen in transverse 

 section, contains cane-sugar in its sappy parenchyma. The analysis 

 shows, for garden Beet, over 14 per cent. ; but in specially selected 

 and cultivated sugar-beets the percentage is higher. It has long been 

 grown as a garden vegetable for winter use ; but latterly it has become 

 the chief European source of Sugar. 



The Parsnip (Pastinaca sativa, L. Umbelliferae) ranks high as a 

 nutritious vegetable. The original type is native in Britain ; it has 

 been cultivated since Roman times. The root, distended by cultivation, 

 is apt to be fibrous on poor soils ; but when well grown it contains a 

 high percentage of digestible carbohydrates. 



The Onion {Allium cepa, L. Liliaceae) was used as a condiment by 

 the Egyptians, Greeks, and Romans. It appears to have originated 

 from a wild species of the Middle East. The distended leaf -bases 

 form a bulb containing a large deposit of sugar. But it is as a 

 condiment that it is specially valued. Other species of Allium give 

 Garlic, Shallots, Chives, etc. 



The Carrot {Daucus Carota, L. Umbelliferae) is the enlarged root of 

 the species native in Britain. 



The Cabbage, Kale, Cauliflower, and Turnip (Cruciferae) are repre- 

 sented by many varieties. They may all be attributed to one or another 

 of four Linnaean species, viz. Brassica oleracea, napus, rapa, and 

 campestris. Some varieties are cultivated for their leaves, as Cabbages ; 

 or for their crowded inflorescences, as Cauliflower ; or for the oil in their 

 seeds, as Colza and Rape ; others again for the fleshy swellings of the 

 root, or lower part of the stem. In Turnips and Swedes the hypocotyl 

 is swollen ; in Kohl-rabi the epicotyl. All of these were ultimately of 

 European or Siberian origin, and some of their ancestral forms grow wild 

 on our coasts. Their cultivation was diffused in Europe before the Aryan 

 invasion. The analyses show that their value as foods is not high, though 

 they contain a fair proportion of digestible proteins and carbohydrates. 

 Celery {Apium graveolens, L. Umbelliferae) is derived from the wild 

 species widely spread from Sweden through Europe and the Near 

 East. It was known to the Greeks. In cultivation it is blanched by 

 earthing up, so as to diminish its bitterness. The feeding value is 

 about equivalent to Winter Kale. 



Spinach (Spinacia oleracea, L. Chenopodiaceae) was not known to 



