Nymphaea immutabilis (black-soil waterlily) is a species of waterlily native to the far north of Western Australia, the Northern Territory, and northern and eastern Queensland, Australia.
Description Vegetative characteristics Nymphaea immutabilis is an annual or perennial plant with globose rhizomes. The round, 70 cm wide leaves have dentate margins. Generative characteristics The flowers are up to 30 cm in diameter, on pedicels or stalks up to 5 m long; the outer petals are blue, grading to white inner petals. The flowers extend up to 50 cm above the water surface. The flowers have four sepals, and 34 petals. The androecium consists of 400 stamens. The gynoecium consists of 9-20 carpels. The globose, 5 cm wide fruit bears numerous 4 mm long, and 2.5 mm wide, rounded seeds with trichomes arranged in irregular rows. The immature seeds are red, but mature to brownish-grey.Dalziell, E. L. (2016). "Seed biology and ex situ storage behaviour of Australian Nymphaea (water lilies): implications for conservation (Doctoral dissertation, PhD thesis. University of Western Australia, Perth, WA)". The seeds have a mechanism of physiological dormancy.
Cytology The chromosome count is n = 42. The genome size is 1408.32 Mb.Chen, F., Liu, X., Yu, C., Chen, Y., Tang, H., & Zhang, L. (2017). "Water lilies as emerging models for Darwin's abominable mystery". Horticulture research, 4.
Reproduction Generative reproduction Flowering occurs from March to November.Stephens, K. M., Dowling, R. M. (2002). "Wetland Plants of Queensland: A Field Guide". p. 56. Kokosinsel (Keeling): CSIRO Publishing.
Taxonomy Publication It was first described by Surrey Wilfrid Laurance Jacobs in 1992.
Type specimen The type specimen was collected by S. Jacobs and J. Clarkson near Mareeba, Queensland, Australia on the 26th of July 1987.Jacobs, S. W. L. (1992). "New species, lectotypes and synonyms of Australasian Nymphaea (Nymphaeaceae)." Telopea, 4(4), 635-641.
Placement within Nymphaea It is placed in Nymphaea subgenus Anecphya.Dalziell, E. L., Baskin, C. C., Baskin, J. M., Young, R. E., Dixon, K. W., & Merritt, D. J. (2019). "Morphophysiological dormancy in the basal angiosperm order Nymphaeales." Annals of botany, 123(1), 95-106.
Separation of Nymphaea kimberleyensis The subspecies Nymphaea immutabilis subsp. kimberleyensis S.W.L.Jacobs was described in 1992. Later in 2011, it was elevated to a separate species Nymphaea kimberleyensis (S.W.L.Jacobs) S.W.L.Jacobs & Hellq.Jacobs, S. W., & Hellquist, C. B. (2011). "New species, possible hybrids and intergrades in Australian Nymphaea (Nymphaeaceae) with a key to all species." Telopea, 13(1-2), 233-243.
Etymology The specific epithet immutabilis, meaning unchanging, references the floral colouration, which does not change as the flower ages.
Conservation The NCA status of Nymphaea immutabilis is Special Least Concern (SL). In the Northern Territory it is categorised as vulnerable.White, M., Albrecht, D., Duguid, A., Latz, P., & Hamilton, M. (2000). "Plant species and sites of botanical significance in the southern bioregions of the Northern Territory. Volume 1: significant vascular plants."Fisher, A., Baker, B., & Woinarski, J. (2002). "Mitchell Grass Downs, Northern Territory."
Ecology Habitat It occurs in swamps, permanent, or temporary waters, billabongs, streams, and rivers.
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