532 ORDER LTLIACE2E, OR LILY TRIBE J DRAGON'S BLOOD. 



are quite harmless, and remarkable either for their use or their 

 beauty. Their stems arise from scaly bulbs, from the bottom of 

 which the roots are developed. These bulbs (and others similar 

 to them) may be regarded as buds, in which the leaves are thick 

 and fleshy, including a store of nutriment for the young plant, 

 and the development of which may be delayed (as in seeds) for 

 an indefinite time, without the loss of their vitality. This is a 

 beautiful adaptation to the circumstances in which these plants 

 are formed to grow ; for they are naturally inhabitants of places 

 which at certain seasons of the year are quite dried up, and where 

 all vegetation would perish, if it were not for some such provision 

 as we find in the bulb. In places like the hard dry karroos of 

 the Cape of Good Hope, where rain falls only during three 

 months in the year, or the parched plains of Barbary, where 

 the ground is rarely refreshed by showers except in the winter 

 months, and on the burning shores of tropical India, be- 

 yond the reach of the tide, and buried in sand, the tempe- 

 rature of which often rises to 180, bulbous-rooted plants are 

 thus enabled to live, and to enliven such scenes with their 

 periodical beauty. 



710. Although, however, the bulbous structure, and herba- 

 ceous vegetation, are very common among the Asphodel tribe, 

 they are not universal ; for many plants have little or no trace 

 of bulbs ; and some species, especially between the tropics, attain 

 considerable size and age as trees. The most gigantic of the 

 order is the Dracaena Draco of the Canary Islands, from which 

 the resinous colouring material named Dragon's Blood, is derived; 

 one of these has been stated to be between 70 and 75 feet high, 

 and 46^ feet in circumference at the base, and to have been a 

 very ancient tree in the year 1496. The principal differences in 

 the structure of the familiar plants of our own climate, are to be 

 found in the varieties of degree, in which the parts of the calyx 

 and corolla are united to each other, and in the formation of a 

 stem covered with leaves, the first rudiment of the arborescent 

 stems and branches of the tropical species. In the Onion, for 

 example, all the parts of the perianth are distinct ; but in the 

 wild blue Hyacinth, or Blue-Bell (as it is more commonly 



