Plants with Extrafloral Nectaries
WORLD LIST OF PLANTS WITH EXTRAFLORAL NECTARIES
Including extranuptial nectaries, circumfloral nectaries, postfloral nectaries and foliar nectaries Nectaries in the Gymnosperms are controversial Because ferns do not have flowers, ferns are listed separately WORLD LIST OF FERNS WITH FOLIAR NECTARIES |
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History
This list was originally compiled by Kathleen H. Keeler, Professor Emerita, School of Biological Sciences, University of Nebraska-Lincoln. Keeler began this list in the late 1970’s but it grew too long to publish and so went into a drawer. The web allowed her to put it up in usable format and to update continually, which is a big improvement over a print publication. In 2013, Keeler teamed up with Marjorie Weber (webermg@umich.edu) and published an analysis of these data: Weber and Keeler 2013. The phylogenetic distribution of extrafloral nectaries in plants 111:1251-1261 link. That paper used with this list as of July 1, 2012 and removed doubtful cases (see paper for details). However, this list no longer matches the paper, since we've added to the list and deleted new of questionable reports.
As of 2014, Marjorie Weber started to take over management of the list, and the list was migrated to a new format and updated by Laura Porturas in 2015. Kathy, Marjorie and Laura are now all working to keep the database updated; please email us with new records not currently listed.
As of 2014, Marjorie Weber started to take over management of the list, and the list was migrated to a new format and updated by Laura Porturas in 2015. Kathy, Marjorie and Laura are now all working to keep the database updated; please email us with new records not currently listed.
Definitions
We are using the term extrafloral nectaries very broadly here. The goal is to include all glands which produce water and sugars, but do not function to attract and reward pollinators, what Delpino (1886) called extranuptial nectaries. However, the function of only a very few extrafloral nectaries have been studied in detail, whether on the leaves, stems or external to the corolla. Furthermore, some leaf nectaries feed pollinators (e.g., Acacia terminalis , Knox et al. 1985). So for now this list seeks to include all nectaries outside of the calyx and makes no claims about function.
Issues and caveats
Issues in a list of extrafloral nectaries include:
1) species not yet seen;
2) nomenclatural confusion, both when names change and because the original specimen was misidentified;
3) mistaking other glandular structures for nectaries
4) recognizing nectary function when there are no surface features
Ideally the presence of an extrafloral nectary is established by demonstrating that the substance produced contains sugars. Without sugars it is a hydathode. A second line of evidence is the attraction of nectar-feeders, especially ants but also wasps and beetles. Feeding is hard to prove, but repeated stopping in the same position at the same spot on the plant is consistent with nectar production. A third approach is to look for nectary structures—raised glands, recessed basins. If some members of the genus or family have extrafloral nectaries in that position, e.g. petiolar nectaries in Ipomoea , we have included other species with the same structures in the same or similar locations.
Angiosperms are arranged alphabetically by genus within the families recognized by the Angiosperm Phylogeny Working Group [Stevens 2001]. The Angiosperm Phylogeny Webpage does not search well by genus: if you need to find where we have put a genus and do not know the family, search on Kew Garden 's web page:http://www.kew.org/data/vascplnt.html
Ferns and gymnosperms are listed separately because, lacking flowers, they don’t have extrafloral nectaries…Nevertheless some have leaf nectaries [fern nectaries] [gymnosperm nectaries]
1) species not yet seen;
2) nomenclatural confusion, both when names change and because the original specimen was misidentified;
3) mistaking other glandular structures for nectaries
4) recognizing nectary function when there are no surface features
Ideally the presence of an extrafloral nectary is established by demonstrating that the substance produced contains sugars. Without sugars it is a hydathode. A second line of evidence is the attraction of nectar-feeders, especially ants but also wasps and beetles. Feeding is hard to prove, but repeated stopping in the same position at the same spot on the plant is consistent with nectar production. A third approach is to look for nectary structures—raised glands, recessed basins. If some members of the genus or family have extrafloral nectaries in that position, e.g. petiolar nectaries in Ipomoea , we have included other species with the same structures in the same or similar locations.
Angiosperms are arranged alphabetically by genus within the families recognized by the Angiosperm Phylogeny Working Group [Stevens 2001]. The Angiosperm Phylogeny Webpage does not search well by genus: if you need to find where we have put a genus and do not know the family, search on Kew Garden 's web page:http://www.kew.org/data/vascplnt.html
Ferns and gymnosperms are listed separately because, lacking flowers, they don’t have extrafloral nectaries…Nevertheless some have leaf nectaries [fern nectaries] [gymnosperm nectaries]
Citation
Please cite this database as:
K.H. Keeler, Porturas, L.D, and Weber, M.G. World list of plants with extrafloral nectaries. www.extrafloralnectaries.org. [date of access].
K.H. Keeler, Porturas, L.D, and Weber, M.G. World list of plants with extrafloral nectaries. www.extrafloralnectaries.org. [date of access].
Please contact us
The updating is ongoing, and comments, clarifications and new information are welcome.
-Marjorie Weber
webermg@umich.edu
-Marjorie Weber
webermg@umich.edu