Lacandonia
| Lacandonia | |
|---|---|
| File:Lacandonia.PNG | |
| Flower of Lacandonia schismatica | |
| Scientific classification Edit this classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Pandanales |
| Family: | Triuridaceae |
| Genus: | Lacandonia E.Martínez & Ramos |
Lacandonia is a mycoheterotrophic plant that contains no chlorophyll and has the unusual characteristic of inverted positions of the male (androecium) and female (gynoecium) floral parts, something that had not been seen in any other plants, with the exceptions of Trithuria and on occasion the related Triuris brevistylis.[1]
Description
Lacandonia is a small, mycoheterotrophic plant that lacks chlorophyll and has a rhizomatous growth pattern. This genus exhibits racemous inflorescences and small, bract-like leaves. The flowers are actinomorphic and are considered "inverted" from the typical flower arrangement–usually 3 (but sometimes two to four) male stamens are in the center of the flower, surrounded by 60 to 80 female pistils. This characteristic, where the positions of the androecium and the gynoecium are reversed, is unique in the known and described taxa of the flowering plants.[2][3][4]
Taxonomy and botanical history
Lacandonia is a genus of mycoheterotrophic plants in the Triuridaceae, with very unusual inverted floral morphology. It has two known species:[5][6]
- Lacandonia schismatica E.Martínez & Ramos 1989 - Chiapas in Mexico
- Lacandonia brasiliana A.Melo & M.Alves 2012 - Paraíba in Brazil
Lacandonia schismatica was first described by Martínez and Clara Hilda Ramos in 1989, who placed the species in its own family, Lacandoniaceae, which itself was placed in the Triuridales.[7] In 1991, Traudel Rübsamen-Weustenfeld suggested that L. schismatica be included in the family Triuridaceae within the genus Sciaphila, Peltophyllum, or its own genus. Another study in 1998 presented data that supports the separation of L. schismatica into its own family.[2] The APG II system transferred the genus to the Triuridaceae and placed that family in the Pandanales.[8] Lacandonia was long considered monotypic, until the discovery of a second species, Lacandonia brasiliana, in Guaribas Biological Reserve in Brazil in 2012.[9]
Evolution
The difficulty expressed in placing the species in the proper family is due to the unique floral morphology. How this inverted position of the androecium and gynoecium evolved is unknown, but some studies have posed hypotheses. Davidse and Martínez suggested that L. schismatica could be one of Richard Goldschmidt's "hopeful monsters", meaning that the inverted floral morphology could have arisen from a macromutation in the genes that control floral development. It is also possible that chromosomal repatterning was the origin of this species.[4]
References
- ↑ Esteban Martinez and Clara Hilda Ramos Lacandoniaceae (Triuridales): Una Nueva Familia de Mexico. Ann. of the Missouri Botanical Garden, Vol. 76, No. 1 (1989), pp. 128-135
- ↑ 2.0 2.1 Vázquez-Santana, S., Engleman, E. M., Martínez-Mena, A., and Márquez-Guzmán, J. (1998). Ovule and seed development of Lacandonia schismatica (Lacandoniaceae). American Journal of Botany, 85(3): 299-304.
- ↑ Márquez-Guzmán, J., Vázquez-Santana, S., Engleman, E. M., Martínez-Mena, A., and Martínez, E. (1993). Pollen development and fertilization in Lacandonia schismatica (Lacandoniaceae). Annals of the Missouri Botanical Garden, 80(4): 891-897.
- ↑ 4.0 4.1 Davidse, G. and Martínez, E. (1990). The chromosome number of Lacandonia schismatica (Lacandoniaceae). Systematic Botany, 15(4): 635-637.
- ↑ Kew World Checklist of Selected Plant Families
- ↑ Davidse, G. & al. (eds.) (1994). Flora Mesoamericana 6: 1-543. Universidad Nacional Autónoma de México, México, D.F.
- ↑ Martínez, E. and Ramos, C. H. (1989). Lacandoniaceae (Triuridales): Una neuva familia de Mexico. Annals of the Missouri Botanical Garden, 76(1): 128-135.
- ↑ The Angiosperm Phylogeny Group. (2003). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society, 141(4): 399-436.
- ↑ Melo, Aline; Alves, Marccus Vinicius da Silva (2012). "The discovery of Lacandonia (Triuridaceae) in Brazil". Phytotaxa. 40: 22–24, f. 1–2. doi:10.11646/phytotaxa.40.1.3.
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