Project 2423: T. A. Dickinson, B. X. Yan, S. Han, M. Zarrei. 2021. Niche Shifts, Hybridization, Polyploidy and Geographic Parthenogenesis in Western North American Hawthorns (Crataegus subg. Sanguineae, Rosaceae). Agronomy. 11 (11):2133.
Specimen: Crataegus macracantha Lodd. ex Loud. (ROM/TRT:TRT00000137)
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Differences in the areal extent of the geographic ranges of sister species are noteworthy. Possible explanations of these differences in particular cases help evaluate and interpret generalizations based on survey data or theory, and contribute to better understanding the biology of individual species. We document range, breeding system, morphology, niche breadth, and leaf vascular architecture in western North American hawthorns for which phylogenetic relationships and ploidy level are known. Species distribution data from herbarium specimens and online databases were analyzed in order to compare climate niches described by BIOCLIM variables. Flow cytometry documented ploidy level and breeding system. Voucher specimens provided morphometric data that were analyzed using uni- and multivariate methods. Black-fruited members of Crataegus subg. Sanguineae of western North America previously identified as hybrids are presumptively self-fertile tetraploids with pseudogamous gametophytic apomixis; their morphologies, geographic ranges, and niche characteristics resemble those of their diploid, sexual parent or are intermediate between them and those of their other parent, one or both of two partially sympatric tetraploid apomicts in red-fruited C. subg. Americanae with much wider distributions. Geographic parthenogenesis (larger range sizes in apomicts, compared to sexuals) may have less to do with adaptation than it does with reproductive assurance in the pseudogamously apomictic and self-compatible hybrids. Wider climatic niche breadth in allopolyploids compared to diploid similarly may be more due to parental traits than to effects of genome duplication per se.

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Article DOI: 10.3390/agronomy11112133

Project DOI: 10.7934/P2423,
This project contains
  • 59 Media
  • 4 Documents
  • 5 Folios
  • 6 Taxa
  • 18 Specimens
Total size of project's media files: 3.69G

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MorphoBank Project 2423
  • Creation Date:
    03 May 2016
  • Publication Date:
    12 October 2021
  • Project views: 27120

    Authors' Institutions

    • University of Toronto

    • Royal Ontario Museum


    member name taxa specimens media
    Tim Dickinson
    Project Administrator
    Madeleine Milne
    Full membership
    Susan Yan

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    Document downloads3Leaf close-ups—measurements and image comparison table (1 download); Leaf venation in Rocky Mountain hawthorn - methods (1 download); Supermatrix TNT format (1 download);