Leiosporoceros

Leiosporoceros
Scientific classification
Kingdom:	Plantae
Division:	Anthocerotophyta
Class:	Leiosporocerotopsida Stotler & Crand.-Stotl. emend Duff
Order:	Leiosporocerotales Hässel[2]
Family:	Leiosporocerotaceae Hässel[1]
Genus:	Leiosporoceros Hässel[1]
Species:	L. dussii
Binomial name
Leiosporoceros dussii (Steph.) Hässel
Synonyms
Anthoceros dussii Steph.

Leiosporoceros dussii is the only species in the hornwort genus Leiosporoceros. The species is placed in a separate family, order, and class for being "genetically and morphologically distinct from all other hornwort lineages."^[3] Cladistic analysis of genetic data supports a position at the very base of the hornwort clade.^[4] Physical characteristics that distinguish the group include unusually small spores that are monolete and unornamented. Additionally, there are unique strands of Nostoc (cyanobacteria) that grow inside the plant parallel with its direction of growth. Unlike other hornworts with symbiotic cyanobacteria that enters through mucilage clefts, the mucilage clefts in Leiosporoceros is only present in young plants and then closes permanently once the cyanobacterial colonies have been established. Also mycorrhiza and pyrenoids are absent.^[5][6] Male plants have been found in Panama.^[2]

References

1. Hässel de Menéndez, Gabriela G. (1986). "Leiosporoceros Hässel n. gen. and Leiosporocerotaceae n. fam. of Anthocerotopsida". Journal of Bryology. 14: 255–259. doi:10.1179/jbr.1986.14.2.255.
2. Hässel de Menéndez, Gabriela G. (1988). "A proposal for a new classification of the genera within the Anthocerotophyta". Journal of the Hattori Botanical Laboratory. 64: 71–86.
3. Duff, R. Joel; Juan Carlos Villarreal; D. Christine Cargill; Karen S. Renzaglia (2007). "Progress and challenges toward a phylogeny and classification of the hornworts". The Bryologist. 110 (2): 214–243. doi:10.1639/0007-2745(2007)110[214:PACTDA]2.0.CO;2.
4. Leebens-Mack, James H.; Barker, Michael S.; Carpenter, Eric J.; Deyholos, Michael K.; Gitzendanner, Matthew A.; Graham, Sean W.; Grosse, Ivo; Li, Zheng; Melkonian, Michael; Mirarab, Siavash; Porsch, Martin; Quint, Marcel; Rensing, Stefan A.; Soltis, Douglas E.; Soltis, Pamela S. (October 2019). "One thousand plant transcriptomes and the phylogenomics of green plants". Nature. 574 (7780): 679–685. doi:10.1038/s41586-019-1693-2. ISSN 1476-4687. PMC 6872490. PMID 31645766.
5. Villarreal, Juan Carlos; Renner, Susanne S. (2012). "Hornwort pyrenoids, carbon-concentrating structures, evolved and were lost at least five times during the last 100 million years". Proceedings of the National Academy of Sciences of the United States of America. 109 (46): 18873–18878. Bibcode:2012PNAS..10918873V. doi:10.1073/pnas.1213498109. PMC 3503201. PMID 23115334.
6. Advances in understanding of mycorrhizal-like associations in bryophytes