GLOSSARY 495 



Chromatin. — Deeply staining material in the nucleus which becomes 

 organized into chromosomes during cell division, and is the carrier of 

 inherited traits. 



Cilium (pi. cilia). — ^Whip-like or hair-like protoplasmic structure pro- 

 jecting from a cell and serving as a locomotor organ in unicellular 

 organisms. 



Coccus. — A spherical bacterial cell. 



Collenchyma. — Temporary supporting tissue made up of cells with un- 

 evenly thickened cellulose walls. 



Colloid. — A condition of matter in which minute particles of one sub- 

 stance are held in suspension in another substance; example, milk. 



Compound leaf. — A leaf in which the blade is divided into separate 

 leaflets; example, hickory or palm. 



Cone. — The reproductive structure of a Gynmosperm, bearing pollen 

 and ovules on exposed scales. 



Coppice. — The sprouts formed by tree stumps after cutting the parent 

 tree. 



Corolla. — The whorl of petals inside the calyx of a flower, usually 

 colored or white. 



Cortex. — Region in stems and roots made up of relatively unspecialized 

 and large parenchyma cells. 



Cotton linters. — The short hairs of the cotton seed, usually too short to 

 be manufactured into textiles. 



Cotyledon. — The part of a seed which functions as an embryonic leaf, 

 contains stored food in many Dicots. 



Cuticle. — The outer waxy covering formed by the epidermis of leaves. 



Cytoplasm. — The portion of the protoplasm exclusive of the nucleus, in 

 which most of the cell activides take place. 



Decay. — The action of bacteria in breaking down complex organic 

 compounds into simple inorganic ones (chiefly water and carbon 

 dioxide). 



Deciduous. — Shedding the leaves at the end of a growing season; not 

 evergreen. 



Dextrin. — A gummy substance formed from starches by acids, heat or 

 enzymes; used in sizings and pastes. 



Dialysis. — Diffusion of a substance through a semi-permeable mem- 

 brane. 



Dicots (Dicotyledons). — The group of Angiosperms with two coty- 

 ledons in each embryo; examples, roses and hickories. 



Diffusion. — Movement of g2ises or substances in solution from a place of 

 high concentration to one of lesser concentration. 



