148 , WAYSIDE WEEDS. 



instead of thick and limited in number. The last 

 roots we have to speak of are the aerial ; we do not 

 mean roots like those of the well-known banana, 

 made still better known by Moore's Knes, " They 

 tell us of an Indian tree/' or of the tropical orchids; 

 but rootlets such as the ivy throws out to the wall 

 against which it chngs, using them as supportSj but 

 ready also to convert them into rootlets should 

 occasion offer. 



We need scarcely teU our readers that roots 

 (except the aerials) serve first the purpose of fixing 

 the plants to which they belong to the soil, and, 

 secondly, that of absorbing moisture along with 

 gases and salts for the nourishment of the plant. 

 This absorption is effected not by the whole root 

 surface, but by the extremities of the fibres or 

 rootlets, these extremities forming what are called 

 spongioles, being so constructed as to admit of 

 more ready absorption of the nutritious fluids. 

 Lastly, a few words are requisite respecting those 

 fleshy masses which we have, for the first time> met 

 with in the form of the turnip or the radish root, 

 the tuber of the orchis, the corm of the crocus, etc. 

 What is their intended use ? They are simply 

 stores of nutriment laid up for aiding the future 

 growth of the plant itself, in its flowering and 

 seeding, or for the nutriment of a new generation 

 of younger plants. Throughout the vegetable 

 kingdom we find this providential storing up for 



