- Morphological classification of plants - 291 A morphological classification of plants, with special reference to the New Zealand alpine flora Halloy, S. Invermay Agricultural Centre, Private Bag, Mosgiel, New Zealand; Tel; +24 893-809 Abstract. A plant is a complex of integrated systems (leaves, leaf groups, stems, roots, inflorescences), coex- isting side by side or superimposed on each other to produce the life form (or physiognomy) of the individual. The classic Raunkiaer classification based fundamental- ly on one character (apex position) is insufficient for the purpose of a functional classification. Five keys are given to determine the categories of: 1) the plant silhouette or general shape resulting from a combination of other systems, with 11 categories propo- sed; 2) the leaf group, with 14 categories; 3) the stem, with 27 categories; 4) the root, with 5 categories; and 5) the inflorescence, with 3 categories. Each plant can be named according to the category or model of each of the five different systems that they most resemble, or by using only the name(s) of systems which are more conspicuous than others. Characters are select- ed primarily for their influence on form and secondarily on size. This scheme allows for detailed studies of a flora in terms of morphological characteristics (alone or in sys- tems), expressed as frequency of occurrence of each character in the flora. Characters can be analysed separa- tely (e.g. entire margined leaves), as a combination of characters (e.g. leaf groups) or as a combination of systems (e.g. rosettes without stems). Thus correlations between environmental variables and plants can be made with more precision than in previous classification sche- mes. The classification also serves as the framework for including additional morphological data and incorpora- ting new models. The New Zealand alpine flora is used as a test case and to exemplify the classification. Keywords: Architecture; Biotypology; Evolution; Growth model; High mountain; Life form. Abbreviations and symbols used in the Keys: See definitions in the main text for an explanation of terms; * = form found only marginally or not at all in alpine environ- ments in New Zealand but closely related to others which are. [ ] = life form of Raunkiaer (as specified by Ellenberg & Mueller-Dombois 1965/66; see also Mueller-Dombois & Ellenberg 1974) which overlap partly with the corresponding category, and / or Hallé & Oldeman (1970) models; [ne] = no equivalent in the Raunkiaer system. L = length; Lf = leaf; LfG = leaf group; LGrS = length of green support; NL per LfL = number of leaves per length of stem equal to one leaf length; W = width. Nomenclature: Cheeseman (1925), Allan (1961) and Moore & Edgar (1970), as updated in Connor & Edgar (1987). Introduction Since Humboldt (1806), many classifications of plants based exclusively on their morphology have been pro- posed. These have been either purely physiognomical (descriptive, e.g. Humboldt 1806; Du Rietz 1931), func- tional (implying ecological meaning, e.g. Warming 1909; Raunkiaer 1934) or ontogenetic (relating to the develop- ment of the form, e.g. Hallé & Oldeman 1970). Other workers concerned with morphology were less preoccupied with classification of the whole plant but rather searched for the functional meaning of characters by themselves (e.g. Wolfe 1979; Dilcher 1973; Givnish 1979; Werger & Ellenbroek 1978). The characters stud- ied can be expressed as averages for a flora or as fre- quency distributions, and a correlation is obtained be- tween these and environmental factors. This has been shown to have remarkably predictive value (e.g. leaf size, leaf margin). This same character-descriptive approach is also used for physiognomic descriptions of the vegetation (e.g. Dansereau & Arros 1959). Orshan et al. (1984) and Orshan, Le Roux & Montenegro (1984) integrated a mono-character approach for up to 36 Journal of Vegetation Science 1: 291-304, 1990 © IAVS; Opulus Press Uppsala. Printed in Sweden