Frond dimorphism
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Frond dimorphism refers to a difference in ferns between the fertile and sterile fronds.[1] Since ferns, unlike flowering plants, bear spores on the leaf blade itself,[2] this may affect the form of the frond itself. In some species of ferns, there is virtually no difference between the fertile and sterile fronds, such as in the genus Dryopteris, [3]other than the mere presence of the sori, or fruit-dots, on the back of the fronds. Some other species, such as Polystichum acrostichoides (Christmas fern), or some ferns of the genus Osmunda, feature dimorphism on a portion of the frond only.[4] [5]Others, such as some species of Blechnum and Woodwardia, have fertile fronds that are markedly taller than the sterile.[6] [7]Still others, such as Osmunda cinnamomea (Cinnamon fern), or plants of the family Onocleaceae, have fertile fronds that are completely different from the sterile.[8]
Only members of the Onocleaceae and Blechnaceae exhibit a propensity towards dimorphy, while no member of the Athyriaceae is strongly dimorphic, and only some representatives of the Thelypteridaceae have evolved the condition, suggesting a possible close relationship between Onocleaceae and Blechnaceae.[9]
Its importance has been disputed - Copeland for example, considered it taxonomically important,[10] whereas Tryon and Tryon[11] and Kramer[12] all stated that the importance can only be judged in relation to other characteristics.[9]
References
[edit]- ↑ "Fern Structure". www.fs.usda.gov. Retrieved 2026-03-31.
- ↑ "What Are Ferns?". www.fs.usda.gov. Retrieved 2026-03-31.
- ↑ "Know Your Natives – Marginal Wood Fern". Arkansas Native Plant Society. 2017-01-25. Retrieved 2026-03-31.
- ↑ "Polystichum acrostichoides (Michx.) Schott". www.worldfloraonline.org. Archived from the original on 2022-07-03. Retrieved 2026-03-31.
- ↑ "Osmunda", Wikipedia, 2025-10-23, retrieved 2026-03-31
- ↑ "Blechnum spicant (Deer Fern, Hard Fern) | North Carolina Extension Gardener Plant Toolbox". plants.ces.ncsu.edu. Retrieved 2026-03-31.
- ↑ "Woodwardia areolata (netted chain fern): Go Botany". gobotany.nativeplanttrust.org. Retrieved 2026-03-31.
- ↑ "Adirondack Ferns: Cinnamon Fern | Osmundastrum cinnamomeum". wildadirondacks.org. Retrieved 2026-03-31.
- 1 2 S. Chandra; M. Srivastava, eds. (1990). Pteridology in the New Millennium: NBRI Golden Jubilee Volume in Honour of Professor B.K. Nayar. New York, New York, USA: Springer Publishing. pp. 33–34. ISBN 9781402011283.
- ↑ Genera Filicum-the genera of ferns. Waltham, Massachusetts, USA: Chronica Botanica. 1947.
- ↑ Tryon, R. M.; Tryon, A. F. (1982). Ferns and allied plants with special reference to tropical America. New York, New York, USA: Springer Publishing. ISBN 038790672X.
- ↑ Rohwer, J. G.; et al. (1990). Klaus Kubitzki (ed.). The families and genera of vascular plants. New York, New York, USA: Springer Publishing.