Plant societies may also be distinguished with reference to latitude and temperature. There are _tropical societies_, _temperate-region societies_, _boreal_ or _cold-region societies_. With reference to altitude, societies might be classified as _lowland_ (which are chiefly wet-region), _intermediate_ (chiefly mid-region), _subalpine_ or _mid-mountain_ (which are chiefly boreal), _alpine_ or _high-mountain_. The above classifications have reference chiefly to great geographical floras or societies. But there are _societies within societies_. There are small societies coming within the experience of every person who has ever seen plants growing in natural conditions. There are roadside, fence-row, lawn, thicket, pasture, dune, woods, cliff, barn-yard societies. _Every different place has its characteristic vegetation._ Note the smaller societies in Figs. 8 and 9. In the former is a water-lily society and a cat-tail society. In the latter there are grass and bush and woods societies. [Illustration: FIG. 8.--A WET-REGION SOCIETY.] =Some Details of Plant Societies.=--Societies may be composed of _scattered and intermingled plants_, or of dense _clumps_ or _groups of plants_. Dense clumps or groups are usually made up of one kind of plant, and they are then called =colonies=. Colonies of most plants are transient: after a short time other plants gain a foothold amongst them, and an intermingled society is the outcome. Marked exceptions to this are grass colonies and forest colonies, in which one kind of plant may hold its own for years and centuries. In a large newly cleared area, plants usually _first establish themselves in dense colonies_. Note the great patches of nettles, jewel-weeds, smart-weeds, clot-burs, fire-weeds in recently cleared but neglected swales, also the fire-weeds in recently burned areas, the rank weeds in the neglected garden, and the ragweeds and May-weeds along the recently worked highway. The competition amongst themselves and with their neighbors finally breaks up the colonies, and _a mixed and intermingled flora is generally the result_. [Illustration: FIG. 9.--A MID-REGION SOCIETY.]