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REPRODUCTIVE BIOLOGY IN RELATION TO SYSTEMATICS
Author(s) -
Ornduff Robert
Publication year - 1969
Publication title -
taxon
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 81
eISSN - 1996-8175
pISSN - 0040-0262
DOI - 10.2307/1218671
Subject(s) - reproductive isolation , biology , heterostyly , taxon , systematics , evolutionary biology , pollinator , adaptive radiation , taxonomic rank , pollination , ecology , interspecific competition , zoology , taxonomy (biology) , phylogenetics , pollen , population , biochemistry , demography , sociology , gene
Summary Many of the diverse floral characteristics used by taxonomists in assessing relationships among taxa represent adaptations to specific pollinators or pollinating methods. Therefore, the diversity of reproductive methods that occurs within a phylad has a strong influence on the number of taxa that are generally recognized in the phylad. Such evolutionary phenomena as convergence and adaptive radiation of floral patterns influence the taxonomic status of various phylads or the relationships that are seen among them. Incompatibility systems are generally unassociated with morphological distinctions, but are of practical importance in crossing programs designed to test the presence and nature of genetic isolation between species, since an unawareness of their existence may lead to erroneous taxonomic conclusions. Similarly, unilateral incompatibility is discussed in relation to certain practicalities in hybridization programs. Morphological features associated with dioecism and heterostyly are disscussed as a generally overlooked source of potentially very useful taxonomic characters. The importance of adaptations to different pollinators as a basis of interspecific isolating mechanisms is stressed, as are the possible positive evolutionary (and taxonomic) consequences of a breakdown in this isolation. Floral and other characters associated with autogamy are discussed and examples are given where the relationships of autogamous taxa are uncertain because of their highly specialized reduced flowers. It is suggested that taxonomists should make an attempt to understand the reproductive methods of the plants with which they work, since such an understanding will strengthen the foundation upon which taxonomic judgments are made.