Radula javanica
Common names
liverwort
Biostatus
Native
Current conservation status
The conservation status of the New Zealand hornwort and liverwort flora is reassessed using the New Zealand Threat Classification System (NZTCS). A full list is presented, along with a statistical summary and brief notes on the most important changes. This list replaces all previous NZTCS lists for New Zealand hornworts and liverworts which previously had been part of a generic bryophyte conservation status assessment that included mosses. Authors: P.J. de Lange, D. Glenny, K. Frogley, M.A.M. Renner, M. von Konrat, J.J. Engel, C. Reeb and J.R. Rolfe.
Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2020 | At Risk – Naturally Uncommon | Qualifiers: SO
Category
Non-vascular
Structural class
Liverworts
Detailed description
Plants forming patches of loosely intertwined bright green to dark green stems on tree trunks and rocks. Shoots 2000 micrometre wide, 40-50 mm long, irregularly branched, thecal branching common, distinguished from athecal branches by the presence of two small leaf like appendages at their base. Stems up to 120 micrometre diameter, cortical cells undifferentiated, of about 16 cell rows, medullary and cortical cells of similar size, medullar of c.20 cells, internal walls with strong irregular faintly concave trigones, sometimes confluent, medial walls also thickened, cells with irregular outline. strong brown pigment present in all walls, free external wall evenly thickened, to a slightly greater degree than internal walls. Lobes ovoid, rarely slightly falcate, contiguous to weakly imbricate, interior margin reaching opposite stem margin, weakly ampliate at stem insertion, insertion hooked, reaching stem mid-line, dorsal leaf free strip absent, stem obscured in dorsal view. Lobules c.one fifth lobe area, keel straight, relfexed at outer extremity, carinal region rounded, slightly inflated near the base of the lobule, attached to the stem for slightly more than half its interior length, free exterior margin distinctly concave, turning the apex away from the stem, antical margin smoothly rounded its entire length, running directly into the ampliate base, interior free margin never exceeding opposite stem margin. Lobules not imbricated, not obscuring stem in ventral view. One slime papillae present at the lobule apex, another two present near the base of the free interior margin. Insertion longitudinal, hooked apically, not attaining ventral stem midline, ventral leaf free strip 1-2 cell rows wide. Lobe cells isodiametric to hexagonal, thin walled with very faint trigones 18.3-28.9 x 14.5-21.7 micrometre. Lobule cells as for the lobe, though slightly elongated. Cell surfaces smooth. Oil bodies not seen. Rhizoids with brown pigmented walls. Leaves infrequently caducous on all axes, breaking off above lobe join, premeristematic outgrowths rarely seen on the antical margins of lobe still attached to the plants. Fertile material not seen in New Zealand.
Distribution
Indigenous. Kermadec Islands (Raoul Island). Widespread in northern Australia, western Oceania and Indonesia
Substrate details
On basalt lava, breccia and tuff and also on tree trunks. Throughout its world range this species is mostly found on tree trunks in cloud forest.
Threats
Known from very few gatherings but unlikely to be threatened. The bryophyte flora of Raoul Island has scarcely been studied by a trained bryologist. Plenty of habitat exists for this species there and there are no known human-induced threats
Detailed taxonomy
Genus
Family
Synonyms
None
Taxonomic notes
Radula javanica as circumscribed for the New Zealand Botanic Region now includes the Raoul Island endemic Radula erigens (described as R. cordiloba subsp. erigens by Renner (2005) and then elevated to species rank as R. erigens (Renner et al 2013)) and also R. multiflora.
Endemic genus
No
Endemic family
No
Ecology
Fruiting
Has not yet been observed in the wild
Other information
Previous conservation status
The conservation status of the New Zealand hornwort and liverwort flora is reassessed using the New Zealand Threat Classification System (NZTCS). A full list is presented, along with a statistical summary and brief notes on the most important changes. This list replaces all previous NZTCS lists for New Zealand hornworts and liverworts which previously had been part of a generic bryophyte conservation status assessment that included mosses. Authors: P.J. de Lange, D. Glenny, K. Frogley, M.A.M. Renner, M. von Konrat, J.J. Engel, C. Reeb and J.R. Rolfe.
Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2009 | Range Restricted | Qualifiers: DP, SO
Referencing and citations
References and further reading
Renner, M.A.M. 2005: Additions to the Radula (Radulaceae: Hepaticae) Floras of New Zealand and Tasmania. Journal of the Hattori Botanical Laboratory 97: 39-79.
Renner, M.A.M.; Söderstöm, L; Hagborg, A.; von Konrat, M. 2013: Notes on early land plants today. 29. A new combination in Radula (Radulaceae, Marchantiophyta). Phytotaxa 81: 12-14
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (18 August 2007). Description adapted from Renner (2005).