steuart's planter's guide. 257 



tually impede the lateral admission of light, the ten- 

 dency of each is upwards ; and the consequence of 

 this tendency is, that the plant is thereby not de- 

 veloped in its natural and perfect proportions, but is 

 elongated, or drawn up to an undue height. It dis- 

 plays its ramification chiefly near the top ; while the 

 imperfection of its life is manifested in the whole 

 character of its vegetation. In open exposures, on 

 the other hand, the tree developes its existence, in 

 full health and luxuriance. It reaches a height, such 

 as the soil and situation admit, and sufficient to al- 

 low the branches, which are thrown out on every 

 side, to expand their leaves freely to the sun. Not 

 being compelled to concentrate its efforts, in secur- 

 ing a scanty supply of one beneficial influence, all its 

 proportions are absolute and universal, not relative 

 and particular. In such circumstances, therefore, it 

 may be considered as in a full and natural state of 

 perfection. 



" Another condition of vegetable life appears to 

 be an adequate degree of Heat. Within a certain 

 range of temperature, vegetation is positively pro- 

 moted : Below, or above a certain point (the de- 

 gree differing in different species of plants), vegeta- 

 tion is positively checked. To speak only of the 

 latter case, which is briefly expressed by the term 



R 



