432 APPENDIX 



BUD. Growing point of shoot. An undeveloped branch. Leaf 



buds form stem and leaves; mixed buds, both leaves and flowers; 



flower buds, flowers only. 

 CALCIFEROUS GLANDS. Glands opening into the oesophagus of the 



Earthworm which secrete calcium carbonate, probably to neu- 

 tralize acidity of food. 

 CALYX. The outer whorl of modified leaves composing a typical 



flower. Usually green. 

 CAMBIUM. Layer of actively dividing cells which, in the highest 



Flowering Plants, is situated between xylem and phloem of vas- 

 cular bundles, and forms a thin cylinder between wood and bark. 

 CARBOHYDRATES. Compounds of carbon with hydrogen and oxygen^ 



the hydrogen and oxygen being in the same proportion as in 



water (H 2 0). 

 CARPEL. One of the innermost whorl of floral leaves which bear 



the megaspores. A simple pistil or an element of a compound 



pistil. A megasporophyll. 

 CATALYSIS. The acceleration of a chemical reaction by a substance 



which itself remains unchanged (e.g., an enzyme). 

 CELL. A structural and physiological unit mass of protoplasm, 



differentiated into cytoplasm and nucleus. 

 CELL SAP. Water, with solutes, under pressure in a large vac- 



uole in the cytoplasm of certain types of plant cells. Effects 



cell turgor. 

 CELLULOSE. A carbohydrate which characteristically forms the 



walls of plant cells. 

 CENTROSOME. A minute body situated in the center of the aster 



and active during cell division. 

 CHELIPED. The first thoracic appendages, or walking-legs, in the 



Crayfish and its allies. The 'pincer/ 

 CHEMOSYNTHESIS. Manufacture (synthesis) of food material from 



water and carbon dioxide, through energy derived from chemical 



changes involving oxidation instead of directly from sunlight. 



Restricted to special groups of Bacteria. 

 CHEMOTAXIS. Movements of cells (e.g., Paramecium) in response 



to chemical stimuli. 



