ORIGIN OF VELD AND KARROO PLANTS. 45 



z is an extra little corm arising from the new one ; x 

 are the roots. 



Some of the corms are edible, and called " Uintjes." 

 The cultivated leek is an instance of a plant which 

 has a bulb when wild, but has lost it under cultivation. 



In many plants the roots swell into nodules, and 



Fig. 22.— Coi-m of Glad'iolus. A, Longitudinal section : a, last year's, 6, this year's 

 corm; c, flower stem; d, scales; x, roots, b. After removal of the enveloping 

 scales : y, bud, which will develop into next year's corm ; z, bulbil. 



act as reservoirs of water and nourishing matters. 

 Fig. 23 illustrates a South African kind of Asimr'agus 

 which has swollen nodules on its roots, most probably 

 for this purpose. 



Fig. 24 shows an elongated form of root. This 

 closely resembles the swollen end of the underground 

 stem of Ox'alis cer'nua, described above. 



