420 GLOSSARY 



Fniit : a ripened ovary together with any parts of the flower adhering to it. 

 Func'tion (Lat. functio, performance) : the normal action of an organ or organs. 



G 



Gam'etes : sex cells. 



Gan'glion (pi. Ganglia) (Gr. ganglion, Httle tumor) : a mass of nervous matter 

 containing nerve cells which give rise to fibers. 



Gas'tric glands (Gr. gaster, stomach) : digestive glands found in the walls 

 of the stomach. 



Gas'trula (Gr. gaster, stomach) : a cuplike structure formed b}^ the invagina- 

 tion or turning in of the blastula. 



Geot'ropism (Gr. ge, earth ; tropein, to turn) : response to gravity. 



Germ cells : egg or sperm cells. 



Germina'tion : the beginning of growth in a seed or a pollen grain. 



Gill rakers : small spinelike structures attached to gill arches which prevent 

 escape of food. 



Gills : breathing organs for use in water. 



Gland (Lat. glans, an acorn) : an organ which secretes material to be used in or 

 excreted from the body. 



Gly'cogen (Gr. glykus, sweet ; -gen, producing) : animal starch, found in the Uver. 



Guard cells : epidermal cells, found on each side of a stoma. 



Gullet (Lat. gula, gullet) : a muscular canal extending from the pharynx to 

 the stomach ; the esophagus. 



H 



Habit : an acquired reflex act. 



Haemoglo'bin (Gr. haima, blood ; glohos, sphere) : red coloring matter of the 



blood. 

 Hsemoly'sins : substances in blood which destroy foreign red corpuscles. 

 Heliot'ropism (Gr. helios, sun ; tropein, to turn) : response to sunlight. 

 Heredity (Lat. heres, heir) : transmission of quaUties from parent to child. 

 Hermaphroditic (Gr. hermaphroditos, combining both sexes) : having both 



male and female sex organs. 

 Hilum : a scar on the testa left where the seed was attached to the pod. 

 Homol'ogy : likeness in structure and position. 

 Hor'mones (Gr. hormaein, to excite) : substances produced bj^ some of the 



glands of the body which effect a chemical coordination. 

 Hu'mus (Lat. humus, ground) : vegetable mold, a black or dark colored sub- 

 stance formed by the decay of organic substances in the soil. 

 Hy'brid (Lat. hyhrida, mongrel) : the offspring of parents of two different 



species or varieties. 

 Hy'drogen (Gr. hydor, water ; -gen, producing) : a gaseous element foimd in 



water and many other compounds. 

 Hy'giene (Gr. hygeia, health) : a study of the preservation of health. 

 Hypocot'yl (Gr. hypo, under) : the part of the developing embryo which forms 



the root and the lower part of the stem. 



