464 The Living Plant 



by any genealogical courtesies from expanding to fill it. The re- 

 sult is this, that kinds of plants genealogically related have come 

 to acquire very different habits, and hence to belong to very 

 different ecological groups, while the different ecological groups 

 include many kinds having the most different genealogical rela- 

 tionships, a matter which is brought out diagrammatically in the 

 accompanying figure (figure 178). It is with plants as with men, 

 who may be grouped by their blood relationships into families or 

 clans on the one hand, or according to their occupations into 

 trades, businesses, or professions on the other. Sometimes the 

 two arrangements overlap, especially among primitive peoples, 

 but often they do not, particularly in the higher civilizations. 

 These ecological groups of plants have been characterized more or 

 less fully in the preceding pages, and need only be summarized 

 very briefly at this place. 



A SYNOPSIS OF THE ECOLOGICAL GROUPS OF PLANTS 



I. INDEPENDENT PLANTS, or AUTOPHYTES, the highest and most 

 distinctive plants, making their own food by aid of chloroiDhyll, and m- 

 cluding : 



1. Normal Plants, or Mesophytes, living rooted in aerated soil sup- 

 plying enough moisture to permit a wide spread of leaves and stems; 

 mainly Flowering plants, but with many Fern-plants and Moss- 

 plants, commonly massed together into forests which exhibit a canopy 

 of trees, an undergrowth of shrubs, and a carpet of herbs. 



Furthermore, some kinds of Mesophytes are so strongly adapted 

 to some particular condition of life as to rank as separate groups, — viz.. 

 Air plants, or Epiphytes, including members of all the genealogical 

 groups, growing supported upon other plants, and highly adapted 

 to that peculiar habit: Climbers, mostl}^ Flowering plants, whose very 

 slender stems, lean, cling or twine by aid of others up to the light: 

 Trailers, of all groups, which keep flat on the ground as a part of the 

 carpet: Insectivorous Plants, wholly Flowering plants, which sup- 

 plement the scantness of soil nitrogen in the places where they live by 

 capturing and digesting insects through aid of remarkable adaptations: 

 Myrmecophilous Plants, Flowering plants of the Tropics, supposed 

 to attract ants for protection against other insect enemies, but of doubt- 

 ful ecological status at present. 



2. Water Plants, or Hydrophytes, living largely immersed in water 

 from which they take their minerals and gases, and therefore mostly 

 soft-bodied and finely divided ; mainly Algae, but including some Moss- 

 plants, Fern-plants, and Flowering plants. 



