GLOSSARY 247 



Host. A plant or animal wliich nourishes a ])avasit,f"'. 



Hybrid (a mongrel). The offspring ol»t,aine«l l»y the artion of th«' pollen 

 of one species on the pistil of another. The term is also used for 

 tlie offspring of any cross. 



Hydrophyte (water plant). A water plant. 



Hygroscopic (moisture seeing). Expanding or shrinking rea<lily under 

 the influence of moisture. 



Hymenium (a membrane). An expanded fruiting surface of a fungus. 



Hypha, plu. hi/phce (a web). The filament of a fungus. 



Hypocotyl. The portion of an embryo or very young seedling between 

 the cotyledons and the root. 



Hypogynous. A term applied to flowers in which the stamens and peri- 

 anth grow from beneath the ovary. 



Indeterminate. A term applied to stems where the growth in length is 



indefinite because no terminal bud is formed, and to an inflorescence 



where there is no terminal flower. 

 Indusium. In ferns a protective outgrowth from the leaf covering a 



cluster of sporangia or sorus. 

 Inferior ovary. See Epigynous. 

 Inflorescence (flowering). The manner in which the flowers are arranged 



in the flower cluster. 

 Intercellular. Between the cells or among them. 

 Internode. The portion of the stem between two nodes. 

 Involucre (a wrapper). A ring of bracts surrounding several flowers (ir 



their flower stalks. 

 Irritability (easily excited). Sensitiveness to stimuli, such as light, heat, 



gravity, etc. 

 Isogamy (equal gametes). The condition where the pairing gametes are 



similar in form and structure. 



Lamina, plu. lamincc (a layer). The blade of a leaf. 



Leaf trace. The group of fibro-vascular bundles which connects the 



veins of the leaf with the fibro-vascular system of the stem. 

 Lenticel. A roundish or lens-shaped spot on young bark, nuirking the 



former position of a stoma. 

 Leptosporangiate. A term applied to pteridophytes in which the s]>oran- 



giuni arises from a single epidermal cell. 

 Leucoplast (white molded). A protoplasmic body found in oflis in the 



interior of the plant body, often serving as a starch builder, — a 



colorless plastid. 

 Lignin (wood). The thickening material deposited in cell walls to j)rcv 



duce woody tissue. 

 Locule (a little compartment). A cavity or chamber, as of an dvary. 



Medullary (belonging to the marrow). Related to the pith, as the med- 

 ullary rays. 



