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AN OUTLINE 



FIRST PRINCIPLES OF HORTICULTURE. 



I. Genreral Nature op Plants. 



1. Horticulture is the application of the arts of cultivation, multipli- 

 cation, and domestication to the vegetable kingdom. Horticulture and 

 Arboriculture are branches of Agriculture. 



2. The vegetable kingdom is composed of living beings, destitute of sensa- 

 tion, with no power of moving spontaneously from place to place, and 

 called plants. 



3. Plants are organized bodies, consisting Of masses of tissue that is per- 

 meable by fluids or gaseous matter. 



4. Vegetable tissue consists either of minute bladders, or tubes adhering 

 by their contiguous surfaces, and leaving intermediate passages where they 

 do not touch. 



5. Tissue is called Cellular when it is composed of minute bladders, 

 which either approach the figure of a sphere, or are obviously some modi- 

 fication of it, supposed to be caused by extension or lateral compression. 



6. When newly formed it is in a very lax state, and possesses great powers 

 of absorption ; probably on account of the excessive permeability of its 

 membrane, and the imperfect cohesion of its cells. 



7. Cellular tissue, otherwise called Parenchyma, constitutes the soft and 

 brittle parts of plants ; such as pith, pulp, the spaces between the veins of 

 leaves, the principal part of the petals, and the like. 



8. Succulent plants are such as have an excessive developement of cel- 

 lular tissue. 



9. It may be considered the most essential kind of tissue, because, while 

 no plants exist without it, many are composed of nothing else. 



10. Tissue is called Woody Fibre when it is composed of slender tubes, 

 which are conical and closed at each end, and placed side by side. 



11. Woody fibre is what causes stiffness and tenacity in certain parts of 

 plants ; hence it is found in the veins of leaves, and in bark, and it con- 

 stitutes the principal part of the wood. 



12. Vascular Tissue is that in which either an elastic tough thread is 

 generated spirally within a tube that is closed and conical at each end ; or 

 rows of cylindrical cellules, placed end to end, finally become continuous 

 tubes by the loss of their ends. 



13. The most remarkable form of vascular tissue is the Spiral Vessel, 

 which has the power of rolling with elasticity when stretched. 



