FLOWER-GARDENING. 129 



II. Root. 



26. The Root is the part that strikes into the earth when a 

 seed begins to germinate, and which afterwards continues to 

 lengthen beneath the soil. 



27. It is also the part which is sometimes emitted by the 

 stem, for the purpose of absorbing nutriment from the atmo- 

 sphere ; as in Ivy, Air-plants, Vines, etc. 



28. It is distinguished from the stem by the absence of 

 leaves in any state ; of regular leaf-buds (IV.) ; of evaporating 

 pores or stomata (131) ; and of pith in Exogenous plants. 



29. Therefore, such underground bodies as those called 

 Tuber (61) in the Potato, Bulb (96) in the Onion, and solid 

 Bulb or Cormus (61) in the Crocus, are not roots. 



30. The office of the root is to absorb food in a fluid or 

 gaseous state ; and also to fix the plant in the soil, or to some 

 firm support. 



31. The latter office is essential to the certain and reo-ular 



o 



performance of the former. 



32. It is not by the whole of their surface that roots absorb 

 food ; but only by their young and newly formed extremities, 

 called Spongioles. 



33. Hence the preservation of the spongioles in an uninjured 

 state is essential to the i-emoval of a plant from one place to 

 another. 



34. A spongiole consists of very young vascular tissue (12) 

 surrounded by very young cellular substance (5). 



[Some modern botanists discard entirely the idea that there 

 are spongioles on the ends of roots. Dr. Webster says that 

 spongioles are supposed expansions of minute parts, at the ter- 

 mination of radicles, resembling a sponge, for absorbing the 

 nutriment of plants.— S. Edwards Todd.] 



35. Spongioles secrete excrementitious matter, which is un- 

 suitable to the same species afterwards as food ; for poisonous 



6* 



