The following classification of vitality has been widely 

 used: ^4 25 



Class 1 : Well-developed plants which regularly complete their 

 life cycles 



Class 2: Vigorous plants which usually do not complete their 

 life cycles or are poorly developed, and sparsely dis- 

 tributed plants that do spread vegetatively 



Class 3: Feeble plants that never complete their life cycles but 

 do spread vegetatively 



Class 4: Plants occasionally appearing from seed but which 

 do not increase in number, such as ephemeral plants 



As an example of the use of this classification, the species in an 

 Andropogon scoparius stand on Long Island were classified as fol- 

 lows: 20 in class 1, 3 in class 2, 1 in class 3, and 2 in class 4, with 

 two remaining unclassified.''^ The large number of species in 

 class 1 indicates that the resources of this site were very good, per- 

 mitting the functioning of many interactions without serious 

 handicap from competition. When a species is not growing within 

 its range of ecological amplitude, or when the competition with 

 other plants is too severe, one of the first indications is the failure 

 to bloom and fruit. 



The vitality and vigor, as well as phenologic behavior, may be 

 used to differentiate between ecotypes. For example, five climatic 

 ecotypes o{ Deschampsia caespitosa ssp. genuina, all morphologically 

 similar in their natural environments, were grown experimentally 

 in one environment where they differed in height of the tallest 

 stems, number of flower stalks, diameter of the clumps, time of 

 flowering and fruiting, and susceptibility to frost and disease. ^^^ 

 An ecotype growing outside of its natural environment will 

 usually not be so vigorous as when growing within it. During the 

 course of evolution the habitat requirements of ecotypes appar- 

 ently became increasingly exacting, so ecotypes, rather than 

 species, are the best indicators of ecological conditions. Species 

 of wide distribution such as Andropogon scoparius and Bouteloua 

 curtipendula, which grow in a variety of habitats, are often repre- 

 sented by a number of ecotypes with special adaptations enabling 



Aimalytic Characteristics of the CoMiimmaxmity • 91 



