Ludwigia grandiflora

Ludwigia grandiflora is an aquatic plant of the order Myrtales.[1]

Ludwigia grandiflora
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Myrtales
Family:	Onagraceae
Genus:	Ludwigia
Species:	L. grandiflora
Binomial name
Ludwigia grandiflora (Michx.) Greuter & Burdet
Synonyms[1]
Jussiaea grandiflora Michx.

It is closely related and easily confused with Ludwigia hexapetala.[2] The two species can be distinguished at a chromosomal level, because L. grandiflora is hexaploid and L. hexapetala is decaploid.[3] However, they can be distinguished morphologically. L. grandiflora has villous hairs, smaller flowers and smaller pollen grains.[3] Some authorities consider that these differences are too slight to consider these different species and so separate these taxa as two varieties or two subspecies.[4][5]

Invasive species

Ludwigia grandiflora has been listed on the List of Invasive Alien Species of Union concern since 2016[6] and in the United States it is on the South Carolina State-listed Noxious Weed list.[7] It out-competes other plants by forming dense mats at the margins and in ponds.[8] It is introduced to warm temperate areas of North America and Europe and has formed large stable populations, particularly in France.[9]

Ludwigia grandiflora found in the Lower Hillsborough River Wilderness Preserve in Florida.

Life history

Ludwigia grandiflora can, and does, produce viable seed, but it is also highly effective at vegetative reproduction and apparently recruitment of new plants from seed is low.[10] The large showy flowers attract a wide variety of insects. A study in Belgium, where L. grandiflora is introduced, showed that the flowers are visited by a wide variety of insects including bees, Lepidoptera, beetles and hoverflies.[11]

References

1. "The Plant List: A Working List of All Plant Species". The Plant List. Retrieved 27 January 2020.
2. Jacono, Colette. "Identification of common aquatic water-primrose species, Ludwigia, in Florida" (PDF). Retrieved 2020-01-27.
3. Zardini, Elsa M.; Gu, Hongya; Raven, Peter H. (1991). "On the Separation of Two Species within the Ludwigia uruguayensis Complex (Onagraceae)". Systematic Botany. 16 (2): 242. doi:10.2307/2419276. JSTOR 2419276.
4. Ward, Daniel Bertram (2012). "New combinations in the Florida Flora III". Phytologia. 94 (3): 459–485 – via Biodiversity Heritage Library.
5. Nesom, Guy; Kartesz, John (2000). "Observations on the Ludwigia Uruguayensis Complex (Onagraceae) in the United States". Castanea. 65 (2): 123–125. JSTOR 4034110.
6. "List of Invasive Alien Species of Union concern - Environment - European Commission". ec.europa.eu. Retrieved 2020-01-27.
7. "South Carolina State Noxious Weeds List | USDA PLANTS". plants.usda.gov. Retrieved 2020-01-28.
8. "Ludwigia grandiflora - Bugwoodwiki". wiki.bugwood.org. Retrieved 2020-01-28.
9. Dandelot, Sophie; Verlaque, Régine; Dutartre, Alain; Cazaubon, Arlette (2005). "Ecological, Dynamic and Taxonomic Problems Due to Ludwigia (Onagraceae) in France". Hydrobiologia. 551 (1): 131–136. doi:10.1007/s10750-005-4455-0. ISSN 0018-8158. S2CID 46339363.
10. Okada, Miki; Grewell, Brenda J.; Jasieniuk, Marie (2009-10-01). "Clonal spread of invasive Ludwigia hexapetala and L. grandiflora in freshwater wetlands of California". Aquatic Botany. 91 (3): 123–129. doi:10.1016/j.aquabot.2009.03.006. ISSN 0304-3770.
11. Stiers, Iris; Triest, Ludwig (2017-10-01). "Low interspecific pollen transfer between invasive aquatic Ludwigia grandiflora and native co-flowering plants". Biological Invasions. 19 (10): 2913–2925. doi:10.1007/s10530-017-1494-1. ISSN 1573-1464. S2CID 7022310.