MANUAL OF AGRICULTURE. 2^3 



savants that the primary office of the many bright hues, varied 

 scents, and tasted secretions of flowers, is to allure the visitation 

 of the insect tribe for the purpose of pollen transportation. The 

 wind also carries many kinds of pollen dust to its due desti- 

 nation. 



To enter upon the consideration of the countless different con- 

 formation of parts, relation as to numbers and modes of arrange- 

 ment of the flower, would be to transij^ress the limits of this 

 manual. 



The seed, then, is the fertilised matured ovule. It contains, 

 along with a new plant in embryo, a sujjply of nutriment for its 

 sustenance when it begins to germinate, and before it can derive 

 that from the soil direct. The embryo consists of the radicle, or 

 root rudiment, the seed leaves or lobes called cotyledons, and the 

 plumule or young stem. The number of cotyledons affords yet 

 another standard of plant classification. Exogenous stemmed plants 

 have two cotyledons in their seeds, and hence are called dico- 

 tyledonous; endogenous, only one, and are therefore styled mono- 

 cotyledonous; whilst flowerless plants which have no true seeds, 

 and consequently no cotyledons, are named acotyledons. In the pea 

 andbeanthe supply of nutrition is incorporated with the cotyledons; 

 in grains it is quite distinct and separate from them. In the 

 former the cotvledons remain beneath the surface, and are 

 absorbed by the radicle and plumule. From the turnip seed the 

 two cotyledons spring above ground, appearing as two smooth 

 leaves, and only decaying when the rough leaves proper sprout: 

 and develop. It is with these tender cotyledons that the turnip 

 beetle or "fly" works such havoc, consuming them and thereby 

 arrestin^^j the seed functions. All Gfrasses and £!Tains are monocotv- 

 ledonous. The principal food ingredients stored up with the em 

 bryo in the seeds are starch and nitrogenous and phosphatic 

 compounds. The absence of direct light and the presence of aii 

 and moisture are necessary for the germination of the seed. The 

 air and moisture are requisite for effecting chemical changes 

 essential to germination ; the latter softens the seed constituents, 

 and with the oxygen in contact the atoms change places, and 

 soluble compounds are formed. Those are absorbed by the cells 

 of the embryo, its several processes are developed, and the rudi- 

 ments of root and stem produced. 



The complicated bodies, — called the proximate constituents, — 

 elaborated and organised by plant life from the simple inorganic 

 compounds derived from soil and atmosphere, arc classified into 

 three divisions, according to the different kinds of nutrition these 

 subserve in the animal body. The three divisions are as follows : 

 the Amylaceous or Saccharine, OU'aginous, and the Albuminous. 

 The first group is entirely composed of carbon, hydrogen, and 

 oxygen, the two last entering in the exact proportions requisite 



