332 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



GLOSSARY 



Abundant — A frequency term which indicates that the individuals of a species 



constitute a large fraction of all the plants within a specified area. 

 Adaptation — The structural responses which plants develop on becoming adjusted 



to changed environmental conditions. 

 Adiabatic — A change of atmospheric temperature in consequence of compression 



or expansion accompanied by an increase or decrease of atmospheric pressure. 

 Anemometer — An instrument measuring the rate of flow of air past a given 



point. 

 Arborescent — Tree-like in form or size, or both form and size. 

 Association — A plant community with definite physiognomy, ecological structure, 



and general uniformity of floristic composition; showing climax adjustment 



to a particular complex of environmental conditions. 

 Atmomeier — An instrument for measuring the rate of evaporation from a satur- 

 ated surface. 

 Biome — A community composed of both plants and animals. 

 Biotic — Referring to such environmental factors as result from the interrelations 



of living organisms. 

 Blujf — A cliff or a headland, consisting of a broad, steep face, usually with a 



rounded break at the summit. 

 Break — A change of direction in the slope angle at the summit of a cliff or 



bluff. 

 Breccia — A rock composed of angular fragments united by a matrix. 

 Chamaephytes — Low shrubs or semi-shrubs with perennial stems that are woody 



at the base and whose propagating buds for the next season are not over 



30 cm. above the surface. 

 Cismontane — In southern California it refers to the area between the main 



interior mountain masses and the coast, that is, the area draining directly 



to the ocean. 

 Cliff — A high, steep rock or bank, used here to refer to nearly perpendicular 



slopes which have an angular break at the summit. 

 Colony — A group of one or more species of plants which has developed as an 



immediate consequence of invasion. 

 Common — A frequency term indicating that the species may be found without 



difficulty in a specified area. 

 Constancy — The consistent presence of a species in different parts of a given 



area, or in different examples of a plant association. 

 Corrasion — Refers to the action of surface wear by physical processes, as by 



the impact of solid particles driven by wind or water; distinguished from 



corrosion, which is a process of chemical wear. 

 Desiccation — The drying out of a region by increased aridity; the drying out 



of a plant at the end of the growing season. 

 Dominant — The plant species, one or more, exerting control over the habitat, 



usually the largest and most frequent species. 

 Ecesis — The establishment of a plant species in a new area, involving migration, 



germination, development, and repeated reproduction. 

 Edaphic — All characteristics of the substratum in which plants grow. 

 Endemic — A plant whose natural distribution is limited to a certain area, or a 



few nearby areas, used here in a relative sense. 

 Epeirogeny — The process of the surface adjustment of large areas by vertical 



uplift or depression, operating over a long period of time. 

 Exotic — A plant which has been introduced into an area where it is not native. 

 Fades — A portion of a community in which one or more dominants have been 



replaced by other species, the general aspect of the community remaining 



unchanged. 

 Feral — Untamed or uncultivated ; referring here to an animal which has reverted 



from the domesticated state. 

 Floristic — Relating to the species and other taxonomic categories of plants in a 



given community. 

 Forb — A general term for all herbaceous plants which are not grasses. 



