496 PLANTS AND MAN 



Drupe. — ^A fleshy fruit containing a hard inner portion, or stone, sur- 

 rounding the seed; example, cherry. 



Egg. — The female gamete produced during sexual reproduction. 



Elaioplasts. — Special oil-forming plastids found in some plants. 



Embryo. — The undeveloped organism resulting from growth of the 

 fertilized egg or a spore; in the flowering plants, found inside the seed 

 and fruit. 



Endosperm. — ^The food-storage region of a seed, outside of the embryo. 



Entire leaf. — ^A leaf with smooth margin. 



Entomologist. — One who makes a specialty of studying insects and their 

 control. 



Enzyme. — ^A substance, found in plants or animals, which brings about 

 some particular chemical action; an organic catalyst. 



Epidermis. — The outer protective layer of cells in an organism. 



Epiphyte. — ^A plant which lives upon another plant but derives no sus- 

 tenance from it; example, lichen. 



Excurrent. — Tree habit in which the trunk continues as a central axis 

 without large diverging branches; example, pine or spruce. 



Fat. — ^A compound of carbon, hydrogen and oxygen; with a lesser 



amount of oxygen than in carbohydrates. 

 Fertilization. — The union of sperm and egg, or male and female nuclei, 



with consequent fusion to form a single cell, or single nucleus. The 



culmination of sexual reproduction. 

 Fiber. — Slender and thick-walled skeletal cells found in the wood of 



stems and roots. 

 Filament. — Thread-like series of cells attached end to end; a form of 



body common among thallus plants. 

 Fission. — The simplest form of asexual reproduction, involving simple 



cell division; example, bacteria. 

 Fixed oil. — A fatty oil which can not be distilled without changing its 



chemical nature. 

 Flagellum. — Hair-like locomotor structure developed by motile cells. 

 Flower. — The reproductive structure of the sporophyte of an Angio- 



sperm, consisting essentially of stamens and pistils. 

 Fruit. — ^The matured and enlarged ovary of a flower, surrounding the 



seed and functioning for dispersal; in some cases other parts of the 



flower (calyx, receptacle) take part in fruit formation. 

 Fumitory. — Any substance burned as an inhalant, such as tobacco. 

 Fungi. — General term applied to the chlorophyll-deficient thallus plants 



which possess cells with organized nuclei. 



