ECOL'OGY, or CECOL'OGY OF MAN•'S ( from Ok. olKos, oikoR. house + -Xoyict, -/oaia, discourse. front V-yetp, /c9cin, to say). That division of bot any which has to do with the inntual relations between plant organisms and their environment.
reeently the subject.matter of evolm.fy has not been systematically treated, although cer tain phases of the subject. such as pollination, seed-dispersal, protection. symbiosis. have been for some time grouped together and denomi nated 'biology,' especially by Berman authors, as Kerner ( 1887.) , Wiesner ( 1889 ) . and Ludwig ( I895). The first to treat ecology systematic ally was \Varming, of Copenhagen. who, in 1515, gave a ri.stimr- of the ecological factors and their influence. and discussed the ecological plant geog raphy of the world. dividing plants into four groups—viz. hydrophytes, mesophytes, xero phytes, and halophytes 019.v.). In 1898 Schimper gave a much more extended treatment of the world's vegetation. but from a slightly different point of view, basing his main subdivisions on temperature, and discussing in each subdivision the ecological relations of the three types of cli matic formations (forest, grassland. desert). and also, but very briefly, of the edaphic formations or plant societies.
Ecology is as yet but incompletely organized, and the subdivisions here proposed are necessa rily tentative. There are three more or less dis
tinct lines of ecology, as t)ie subject is now stud ied: (1) The ecology of the various plants. their tissues and organs—i.e. the study of the re lation of piants, tissues, and organs to their environment—may be called physiological ecol ogy, since this division of the subject is related to physiology, or may even be classed as a part of it. Physiological eeology has two further subdivisions: _knattanieal ecology, which con cents itself with the origin, development, and meaning of plant tissues, and organographic ecology (or simply organography). which •on cerns itself with the origin. development, and meaning of plant forms and organs. (2) The ecology of edaphie plant societies– i.e. the study of their origin, development, and life relations— may be called physiographie ecology, since this subject is related to physiography, or may even be classed as a part of it. (3) The ecology of climatic plant formations—i.e. the study of the great forest. grass, and desert formations of the globe in relation to climatic be called geograillie ecology, or ecological phyto geography. slime this subject is essentially a part of geography. lt is more convenient to speak of this third subdivision under the head of