Dendroceros Explained

Dendroceros is a genus of hornworts in the family Dendrocerotaceae.[1] The genus contains about 51 species native to tropical and sub-tropical regions of the world.

Description

The epiphytic and epiphyllous Dendroceros is the only desiccation-tolerant hornwort genus.[2] The gametophyte is yellowish-green and usually less than one-half cm wide. The thallus branches in a bifurcating pattern. In the subgenus Apoceros, there are cavities in the central strand of the thallus. The edges of the thallus are only a single layer of cells thick and have an undulating margin. It is common to find symbiotic colonies of blue-green bacteria (usually Nostoc) growing among the cells. Under a microscope, the epidermal cells have trigones.

The sporophyte is erect when mature, growing up to 5 cm tall. Unlike many hornworts, the surface of the Dendroceros sporophyte lacks stomata, as do the sporophytes of the related genera Megaceros and Nothoceros.[3] [4] [5] The interior of the sporophyte differentiates into a central column and a surrounding mass of spores and elater cells, with a distinct spiral. The spores are green and multicellular with an ornamented surface.[6]

Classification

Current classification by Söderström et al. 2016.[7]

Genus Dendroceros Nees 1846

Habitat

Dendroceros grows on humid ground, rocky outcrops, and on the sides of trees. Its name literally means "tree horn".

Notes and References

  1. Renzaglia, Karen S. & Kevin C. Vaughn. (2000) "Anatomy, development and classification of hornworts", pages 1-20 in A. Jonathan Shaw & Bernard Goffinet (Eds.), Bryophyte Biology. (Cambridge: Cambridge University Press).
  2. 6025193 . 2018 . Pressel . S. . Renzaglia . K. S. . (Dicky) Clymo . R. S. . Duckett . J. G. . Hornwort stomata do not respond actively to exogenous and environmental cues . Annals of Botany . 122 . 1 . 45–57 . 10.1093/aob/mcy045 . 29897395 .
  3. Book: Schuster, R.M. . The Hepaticae and Anthocerotae of North America East of the Hundredth Meridian . Field Museum of Natural History . 1992 . 0-914-86821-7 . 6 . Chicago . 825–858 . en.
  4. Duckett . J.G. . Ligrone . R. . 2003 . There are many ways of making water-conducting cells but what about stomata? . Field Bryology . 82 . 33.
  5. Frangedakis . E. . Shimamura . M. . Villareal . J.C. . Li . F.-W. . Tomaselli . M. . Waller . M. . Sakakibara . K. . Renzaglia . K.S. . Szövényi . P. . 2021 . The hornworts: morphology, evolution and development . New Phytologist . 229 . 740 . 10.1111/nph.16874.
  6. Parallel Evolution of Endospory within Hornworts: Nothoceros renzagliensis (Dendrocerotaceae), sp. nov. . 41416933 . Villarreal A. . Juan Carlos . Campos S. . Laura Victoria . Uribe-M. . Jaime . Goffinet . Bernard . Systematic Botany . 2012 . 37 . 1 . 31–37 . 10.1600/036364412X616594 . 86328103 .
  7. Söderström . 2016 . World checklist of hornworts and liverworts . PhytoKeys . 59 . 1–826. 10.3897/phytokeys.59.6261. etal . 26929706 . 4758082 . free .

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