Legume Genomics and Genetics 2024, Vol.15, No.5, 210-220 http://cropscipublisher.com/index.php/lgg 211 research thoroughly discusses the implications of the findings for conservation efforts and future research directions, aiming to explore the evolutionary history and ecological significance of winged papilionaceous flowers within the legume family. 2 Evolutionary History of Winged Papilionate Flowers 2.1 Origins in the fossil record The earliest known fossils of papilionate flowers date back to the Late Cretaceous period. Fossil evidence from this era, such as the winged fruits of Friisifructus aligeri from Western North America, provides crucial insights into the diversity and evolutionary history of angiosperms (Tang et al., 2023). Additionally, fossilized flowers from the early Palaeocene of Patagonia, Argentina, with affinities to the Schizomerieae tribe, offer further evidence of early papilionate floral structures (Figure 1) (Jud et al., 2018). The evolutionary significance of winged structures in papilionate flowers is highlighted by their role in effective ecological interactions and dispersal strategies. For instance, the Dipterygeae clade, which has maintained winged papilionate floral traits for approximately 30 million years, demonstrates the evolutionary conservatism of these structures. This conservatism has likely contributed to the clade's successful persistence across various Neotropical biomes (Carvalho et al., 2023a). The presence of winged fruits in the Cladrastis clade also underscores their importance in the biogeographic history and adaptation to different environments (Duan et al., 2019). Figure 1Lacinipetalum spectabilumspecimens from locality PL-2 (Adopted from Jud et al., 2018) Image caption: (A) Flower in transverse view, showing 9-merous structure, sepals narrow-lanceolate, laciniate petals alternating with sepals, stamens (at arrowhead) and floral disc 2.5 mm across. MPEF-Pb 8423. (B) Flower in transverse view, showing 10-merous structure, sepals narrow-lanceolate, laciniate petals alternating with sepals, stamens not preserved, and floral disc 3.9 mm across. MPEF-Pb 8517. (C) Detail of sepal venation. Note three main parallel veins supplying the sepals and two faint intramarginal veins. MPEF-Pb 8433a. (D) Close-up of a narrow, flabellate petal incised into at least eight secondary segments. MPEF-Pb 8447a. (E) Close-up of a narrow, flabellate petal incised into nine segments. MPEF-Pb 8 414 a. (F) Flower in longitudinal view, showing stout pedicel, shallow floral cup and superior ovary covered in fine trichomes (at arrow) and two free stylodia. MPEF-Pb 8455. (G) Flower in longitudinal view, showing stout pedicel, shallow floral cup, sepals (s), laciniate petals (p) and two stylodia emerging from the apex of the ovary (at arrows). MPEF-Pb 8444a. (H) Flower in longitudinal view illuminated under epifluorescence. Note the two brightly fluorescing anthers and pubescent surface of the ovule (hairs at arrowhead). MPEF-Pb 8452a. Scale bars: (A, B) = 3.0 mm; (C–E) = 2.0 mm; (F, G) = 2.5 mm; (H) = 1.5 mm (Adopted from Jud et al., 2018)
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