

40 ORGANS AND CHEMISTRY OF PLANTS. 



then piled up endwise around these. Earth is added or water thrown 

 on to subdue the burning, if too great, and air is admitted if it be too 

 slow. Four days is generally required for the burning. 



The Organs of Plants. 



(Necessary to nutrition and growth.) 

 The Root its neck, radical and stalk. 

 The Stem its branches and their branchlets. 

 The Bud and its scales. 

 The Leaf and leafets. 

 Appendages prickles, thorns, glands, stings, scales, tendrils, etc. 



(Necessary to reproduction.) 



The Flower The Calyx, its sepales, or leaves The Corolla, its 



petals, or leaves The Nectary The Stamen, its filaments, anther 



and polen The Pistil, its stigma, style, ovary or germ, and 



ovules. 



The Fruit The pericarp, its cells, valves, etc. 



The Seed columella hilam, albumen, cotyledons. 



Embryo, its radical and plume. 



The accompanying cut exhibits all the prin- 

 cipal parts of a plant. 



a the root ; b the bulb ; c root-leaves ; d stem ; 

 e stem-leaves ; / branches ; g flower-stalk ; 

 h flowers. The whole is the Bulbous Butter 

 Cup. 



VEGETABLE ORGANIC CHEMISTRY. 



The elementary parts of vegetables, we repeat, are carbon, hydro- 

 gen, nitrogen and oxygen. These are always present in plants, and 

 they produce by their union all the various principles of which plants 

 consist. The principal parts are composed of carbon, with oxygen 

 and hydrogen ; these last two being in the relative proportion in which 

 they form water. These parts are the woody -fibre, starch, sugar and 

 gums. 



Another class of vegetable substances, such as the organic acids, 

 contain oxygen in a greater proportion than is necessary to form water 

 with the hydroeen, and they thus have an excess of oxygen. A third 

 class of vegetable compounds, such as the volatile and fixed oils, wax, 

 and the resins, contain carbon and hydrogen, but no oxygen ; or less 



