Dendroceros is a genus of hornworts in the family Dendrocerotaceae. 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. 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. 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.
Classification
Current classification by Söderström et al. 2016.
Genus Dendroceros <small>Nees 1846</small>
- D. australis <small>Stephani 1909</small>
- D. crassicostatus <small>Stephani 1917</small>
- D. exalatus <small>Stephani 1909c</small>
- D. gracilis <small>Stephani 1917b</small>
- D. humboldtensis <small>Hürlimann 1960</small>
- D. rarus <small>Stephani 1917b</small>
- D. reticulus <small>Herzog 1950b</small>
- D. subtropicus <small>Wild 1893</small>
- D. tahitensis <small>ÃÂ
ngström 1873</small>
- D. vesconianus <small>Gottsche ex Bescherelle 1898</small>
- D. wattsianus <small>Stephani 1909</small>
- Subgenus (Cichoraceus) <small>Peñaloza-Bojacá & Maciel-Silva 2019</small>
- D. cichoraceus <small>(Montagne 1845) Stephani 1916</small>
- Subgenus (Dendroceros) <small>Nees 1846</small>
- D. acutilobus <small>Stephani 1909</small>
- D. adglutinatus <small>(Hooker & Taylor 1845) Gottsche, Lindenberg & Nees 1846</small>
- D. allionii <small>Stephani 1917</small>
- D. breutelii <small>Nees 1846</small>
- D. crassinervis <small>(Nees 1846) Stephani 1917</small>
- D. crispus <small>(Swartz 1788) Nees 1846</small>
- D. foliicola <small>Hasegawa 1980</small>
- D. herasii <small>Infante 2010</small>
- D. javanicus <small>(Nees 1830) Nees 1846</small>
- D. paivae <small>Garcia, Sérgio & Villarreal 2012</small>
- D. rigidus <small>Stephani 1917</small>
- D. subplanus <small>Stephani 1909</small>
- D. tubercularis <small>Hattori 1944</small>
- D. validus <small>Stephani 1917</small>
- Subgenus (Nodulosus) <small>Peñaloza-Bojacá & Maciel-Silva 2019</small>
- D. africanus <small>Stephani 1917</small>
- D. borbonicus <small>Stephani 1892</small>
- D. crispatus <small>(Hooker 1830) Nees 1917</small>
- D. granulatus <small>Mitten 1871</small>
- D. japonicus <small>Stephani 1909</small>
- Subgenus (Apoceros) <small>Schuster 1987b</small>
- D. cavernosus <small>Hasegawa 1980</small>
- D. cucullatus <small>Stephani 1923</small>
- D. difficilis <small>Stephani 1917</small>
- D. muelleri <small>Stephani 1889</small>
- D. ogeramnangus <small>Piippo 1993</small>
- D. pedunculatus <small>Stephani 1909</small>
- D. seramensis <small>Hasegawa 1986</small>
- D. subdifficilis <small>Hattori 1951</small>
Habitat
Dendroceros grows on humid ground, rocky outcrops, and on the sides of trees. Its name literally means "tree horn".
References
External links