Ecology (ḗ-kŏl′ ṓ-jy̆), often spelled œcology. In botany it is that division of the subject which deals with plants in relation to their environment. This environment includes both the physical conditions in which plants live and other plants and animals. There are two prominent phases of ecology. One considers the individual plant as it relates its organs to the environment. For example, the relation of leaves to light, of roots to the soil, of flowers to insects; the protection of various organs or the whole plant against drouth, cold, intense light, poor nutrition; the arrangements for the dispersal of spores and seeds; and many other subjects all belong to this phase of ecology. The other phase of the subject deals with plants associated together in what are called plant-societies. Plants are not scattered at haphazard over the surface of the earth, but are organized into definite societies or communities, as a forest-society, a meadow-society, a swamp-society, etc. These societies are determined by varying combinations of numerous factors, such as temperature, water, soil, light, wind, and they are as numerous as the possible combinations of these factors. This study of plant-societies merges into the study of the natural floras of the world, which are combinations of societies; and this in turn leads to the study of geographical botany. The study of the conditions which determine floras is often called floristics; while the combination of plant-societies, floristics and geographical botany is sometimes called phytogeography.
