Nymphaea rudgeana is a species of waterlily native to the region spanning from Mexico to tropical South America.

Description Vegetative characteristics

The ovoid to subglobose rhizome may exceed 7 cm in length and 8 cm in width. It is not stoloniferous. Its leaves are thick and leathery, round to kidney-shaped or broadly heart-shaped. The leaf blade is 17-18 cm long and 19-21 cm wide. In deeper water, they can grow up to 35 cm. The margin is dentate and has uneven, blunt teeth, although towards the apex the margin is almost entirely smooth. It is the sole member of its subgenus featuring leaves with dentate margins. However, it also produces submerged leaves with entire margins, if it grows in flowing water. The adaxial leaf surface is shiny and light green with some red colouration in the centre and towards the edge. Younger leaves exhibit brownish red spotting. The abaxial leaf surface, which features protruding leaf venation, displays a brownish-purple colouration with irregular spotting. The petiole is reddish-brown, up to 9 or 11 mm wide, glabrous and has 2 primary, as well as 4 to numerous secondary air canals. From each leaf base, 6-7 roots emerge.

Generative characteristics

The flower has four green or pink sepals, with or without blackish stripes. They are elliptic in shape with an acute to obtuse apex. The white to pink petals are gradually transitioning into stamens.Lima, C. T. D. (2018). "Flora das cangas da Serra dos Carajás, Pará, Brasil: Nymphaeaceae." Rodriguésia, 69, 153-156. The floral fragrance has been described as lemon scented.Lóczy, L. (1897). "Resultate der wissenschaftlichen Erforschung des Balatonsees." p. 33. Austria: In Kommission von E. Hölzel. The rich, fruity odour is said to resemble the fragrance of Nymphaea amazonum.Prance, G. T. (1980). A Note on the Pollination of Nymphaea Amazonum Mart. & Zucc. (Nymphaeaceae). Brittonia, 32(4), 505–507. https://doi.org/10.2307/2806159

Cytology The diploid chromosome count is 2n = 42.

Reproduction Vegetative reproduction Asexual reproduction is not known to occur in this species. Both stolons and proliferating pseudanthia are absent in this species.Pellegrini, M. O. O. & Jardim Botânico do Rio de Janeiro. (n.d.-b). Nymphaea rudgeana G.Mey. Flora E Funga Do Brasil. Retrieved November 26, 2023, from https://floradobrasil.jbrj.gov.br/FB10949 Generative reproduction Cross pollination of the protogynous flowers occurs frequently. However, since the stigma remains receptive in the second day, which is when the pollen is released, autogamy is possible as well. The seeds are very numerous. In one case, 4365 seeds were found in a single fruit. A range of 1000 to 8000 seeds has also been reported.Conard, H. S. (2015). The Waterlilies: A Monograph of the Genus Nymphaea (Classic Reprint). pp. 204-206. USA: FB&C Limited.

Habitat It can grow in salty or brackish water.Wiersema, J. H. (1988). Reproductive Biology of Nymphaea (Nymphaeaceae). Annals of the Missouri Botanical Garden, 75(3), 795–804. https://doi.org/10.2307/2399367Camargo, A. F. M., & Florentino, E. R. (2000). "Population dynamics and net primary production of the aquatic macrophite Nymphaea rudgeana CF Mey in a lotic environment of the Itanhaém River basin (SP, Brazil)." Revista Brasileira de Biologia, 60, 83-92. It has been observed growing in shallow waters of 20-100 cm in depth at river margins. It has also been found growin in an artificial lake with slight water flow.

Taxonomy Type specimen The type specimen was collected in Guyana by Rodschied.Nymphaea rudgeana | International Plant Names Index. (n.d.). Retrieved November 27, 2023, from https://www.ipni.org/n/281442-2Wiersema, J. H. (1987). A monograph of Nymphaea subgenus Hydrocallis (Nymphaeaceae). Systematic Botany Monographs, 1-112.

Placement within Nymphaea It is a member of Nymphaea subg. Hydrocallis. However, it was speculated that Nymphaea rudgeana may be an ancient hybrid involving Nymphaea subgenus Lotos.Borsch, T., Hilu, K. W., Wiersema, J. H., Löhne, C., Barthlott, W., & Wilde, V. (2007). "Phylogeny of Nymphaea (Nymphaeaceae): evidence from substitutions and microstructural changes in the chloroplast trnT-trnF region." International Journal of Plant Sciences, 168(5), 639-671.

Etymology The specific epithet rudgeana honours Anne Rudge.Stearn, W. T., & Williams, L. H. J. (1957). Martin’s French Guiana Plants and Rudge’s “Plantarum Guianae rariorum Icones.” Bulletin Du Jardin Botanique de l’État a Bruxelles, 27(2), 243–265. https://doi.org/10.2307/3666961

Ecology Pollination

The beetle species Cyclocephala castanea and Cyclocephala verticalis visit Nymphaea rudgeana flowers.Gottsberger, G. (1986). Some Pollination Strategies in Neotropical Savannas and Forests. Plant Systematics and Evolution, 152(1/2), 29–45. http://www.jstor.org/stable/23673697M Cramer, J., Meeuse, A. D. J., & Teunissen, P. A. (1975). "A note on the pollination of nocturnally flowering species of Nymphaea." Acta Botanica Neerlandica, 24(5/6), 489-490.Prance, G. T., & Anderson, A. B. (1976). "Studies of the floral biology of neotropical Nymphaeaceae." 3. Acta Amazonica, 6, 163-170. The insects are not trapped inside the flowers overnight. There have however been reports of consistently finding dead insects within the flowers.Henkel, F. (1907). Das Buch Der Nymphaeaceen Oder Seerosengewächse Von Fr. Henkel, F. Hehnelt und L. Dittmann. pp. 74-75. Deutschland: Friedrich Henkel.

Conservation In Puerto Rico it is a rare species facing habitat destruction.Woodbury, R. O. (1975). "Rare and Endangered Plants of Puerto Rico: A Committee Report." p. 61. United States: U.S. Department of Agriculture, Soil Conservation Service. The IUCN conservation status is not evaluated (NE).

Uses Foliage and flowers are used as emollients by the Palikur people of French Guiana.Hegnauer, R. (2013). Chemotaxonomie der Pflanzen: Eine Übersicht über die Verbreitung und die systematische Bedeutung der Pflanzenstoffe. p. 136. Germany: Birkhäuser Basel. Various other ethnobotanical uses were also reported: Decoctions were used for cases of morphea, as a drink it was used against erysipelas, and it has been used as treatment of facial tumours, toothaches and leprous wounds."Berichte der Deutschen Pharmaceutischen Gesellschaft." p. 285. (1897). Germany: R. Gaertners Verlagsbuchhandlung. The seeds are used as food by native people.

Cultivation It is very rare in cultivation, although it may be easily cared for.Breukel, H. (n.d.-b). Nymphaea rudgenana G.F.W. Meyer - syn. blanda Planch. Seerosenforum.de Das Portal Der Seerose. Retrieved November 26, 2023, from https://www.seerosenforum.de/Gattung/Hydrocallis/rudgenana/rudgenana.aspxNymphaea rudgeana. (n.d.). Flowgrow. Retrieved November 26, 2023, from https://www.flowgrow.de/db/aquaticplants/nymphaea-rudgeanaBIOTOPE AQUARIUM Project, & Khardina, N. (2022, September 5). Nymphaea rudgeana G.Mey. Biotope Aquarium Project. Retrieved November 26, 2023, from https://biotopeaquariumproject.com/plant/nymphaea-rudgeana-ig-sauvaudaua-nkhardina/Oczkowski, Y. (n.d.). Les plantes : Nymphaea rudgeana. Aquavipare. Retrieved November 26, 2023, from http://www.aquavipare.fr/plantes/plante_detail.php?PlanteNomScientifique=Nymphaea+rudgeana It should be cultivated in high light conditions in rich, loamy fertile substrate at temperatures of 23 - 29 °C.

References