| Radula visianica | |
|---|---|
Scientific classification  | |
| Kingdom: | Plantae |
| Division: | Marchantiophyta |
| Class: | Jungermanniopsida |
| Order: | Porellales |
| Family: | Radulaceae |
| Genus: | Radula |
| Species: | R. visianica |
| Binomial name | |
| Radula visianica | |
Radula visianica is a species of liverwort in the family Radulaceae. [2] It is endemic to the European Alps. It was thought to be extinct since 1938 but was rediscovered in 2014 in Austria. [3]
Radula visianica was first described by the Italian botanist Caro Massalongo in 1904, [4] based on specimens he had collected in February 1878. The species name honours Roberto de Visiani, a 19th-century botanist who owned a villa near the original collection site in the Euganean Hills of northeastern Italy. The species belongs to the genus Radula in the family Radulaceae, within the order Porellales of the liverworts (Marchantiophyta). The type specimen (holotype) was collected "at Mt. Sengiari above Torreglia, not far from the place where the villa that once belonged to the late professor R. de Visiani was located." The holotype is housed in the herbarium of Verona (VER), with additional type material (isotypes) preserved in the Farlow Herbarium at Harvard University (FH) and the Swedish Museum of Natural History in Stockholm (S). [3]
Initially, researchers believed R. visianica might have tropical affinities due to some of its morphological features. However, its rediscovery in alpine environments and subsequent study suggests it is actually a cold-adapted species that evolved in Europe. [3]
Radula visianica is a small, green to yellowish-green plant that grows in patches. Individual shoots are typically 0.3–1.5 mm (0.012–0.059 in) wide and can reach up to 20 mm (0.79 in) in length. The plant has two distinct parts to each leaf: a larger upper lobe (dorsal lobe) and a smaller lower lobe (ventral lobe), which is a characteristic feature of the genus Radula. [3]
The species is notable for its highly variable appearance depending on its growing conditions. In exposed, cold locations, it develops compact forms with inflated lower lobes, while in protected, moist locations, it grows larger with flatter, more elongated lobes. This adaptability helps it survive in different environmental conditions. [3]
While initially thought to be a tree-dwelling species, R. visianica primarily grows on north-facing dolomite rocks (a type of limestone rich in magnesium) in mountainous areas. It is typically found at elevations between 150–1,800 m (490–5,910 ft) above sea level, usually in moist to wet conditions. The species often grows among other small plants, including mosses and algae. [3]
As of 2016, R. visianica was known from only seven locations, including two historical sites in Italy (including the original discovery site near Padua), and five more recently discovered sites in the Austrian Alps. Scientists believe the species may also exist in other mountainous regions of Europe with similar geological conditions, such as the Apennines, Dinarides, Carpathians, and Pyrenees, though it has not yet been found in these areas. [3]
Radula visianica was listed as extinct on the IUCN Red List until its rediscovery in Austria. The species appears to be vulnerable to climate change and air pollution, particularly in lower elevation sites. Its apparent preference for dolomite rock in mountain environments may represent an adaptation that has helped it survive during periods of climate change. [3] The species is categorised in the European Red List of bryophytes as critically endangered. [5]
The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information.
Marchantiales is an order of thallose liverworts that includes species like Marchantia polymorpha, a widespread plant often found beside rivers, and Lunularia cruciata, a common and often troublesome weed in moist, temperate gardens and greenhouses.
Marsupella profunda, the western rustwort, is a liverwort native to Europe and known only from Portugal and Great Britain (Cornwall) and has been sighted in the Canary Islands. It is a small reddish liverwort and can be confused with Marsupella sprucei which has a more widespread distribution.
Bazzania bhutanica is a species of liverwort in the family Lepidoziaceae. It is a critically endangered species known only from the eastern Himalayas of Bhutan and northeast India.
Fulfordianthus evansii is a species of liverwort in the family Lejeuneaceae. It is found in Belize, Costa Rica, Guatemala, and Panama. Its natural habitat is subtropical or tropical moist lowland forests.
Hymenostylium gracillimum is a species of moss in the family Pottiaceae. It is an endangered species found in Austria and Russia.
Herbertus borealis is a species of liverwort in the family Herbertaceae known as northern prongwort. It was described in 1970 by Alan Crundwell. It is endemic to Scotland, where it is found only in the Beinn Eighe nature reserve, and lives in dwarf shrub heath alongside other large liverworts such as Anastrophyllum donnianum, Bazzania tricrenata and Pleurozia purpurea. A closely related species, described in 2012 as Herbertus norenus and known as "Viking prongwort", is known from Shetland and Norway and was formerly confused with H. borealis.
Colura irrorata is a species of liverwort in family Lejeuneaceae. It is endemic to Ecuador. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss. The species was previously known as Myriocolea irrorata, but was transferred to Colura in 2012 following a phylogenetic analysis of nuclear and plastid molecular markers and a reinterpretation of morphological characters.
Phycolepidozia exigua is a species of liverwort in the family Cephaloziellaceae. It was thought to be the only species in the genus until a new species from India, Phycolepidozia indica, was found in 2014. Phycolepidozia exigua is endemic to Dominica, where it is critically endangered. Its natural habitat is subtropical or tropical moist lowland forests.
Radula jonesii is a species of liverwort in the family Radulaceae, first described in 1988 from specimens collected in the Anaga Mountains of Tenerife. Endemic to Macaronesia, this dark to olive-green liverwort is known from five locations on Madeira Island and one location on Tenerife, where it grows as both an epiphyte on trees such as Laurus novocanariensis and as a lithophyte on shaded rocks in old growth laurel forest ecosystems between 800–1,000 m (2,600–3,300 ft) altitude. The species is distinguished by its procumbent growth habit, pinnately branched stems measuring 10–15 mm (0.4–0.6 in) in length, and distinctive cellular features including uniformly thin-walled leaf cells. Classified as Endangered due to its restricted range and small population size, R. jonesii faces threats from climate change, habitat degradation, and tourism pressure, though its habitat receives protection through various conservation designations including UNESCO World Heritage status.
Schistochila macrodonta is a endangered species of liverwort in the family Schistochilaceae. It is found in Bhutan and China. This large, unbranched liverwort, characterised by its shoots measuring 4–6 cm (1.6–2.4 in) in length and distinctive two-lobed leaves with smooth margins, is found only in high-altitude temperate and subtropical forests of Bhutan and China's Yunnan Province, at elevations between 2,730–3,580 m (8,960–11,750 ft). The species has reddish-brown rhizoids and the unusual presence of bicellular propagules at its leaf tips. Its extremely restricted distribution, known from only a few locations spanning less than 500 km2 (190 sq mi), has led to its classification as endangered on the IUCN Red List due to ongoing habitat decline.
Radula is a genus of liverwort in the family Radulaceae. The genus includes 248 species of small plants that typically grow as green, scaly patches on tree trunks, logs, or rocks in moist environments. It is distinguished from other liverworts by several unique features, including the production of root-like structures (rhizoids) exclusively from leaf surfaces and characteristic branching patterns. The plants have rounded, overlapping leaves consisting of two unequal lobes, with considerable variation in structure across species. Following a major taxonomic revision in 2022, the genus comprises five subgenera with distributions ranging from tropical to temperate regions. The oldest known fossil species, R. cretacea, found in Burmese amber, dates to the Cenomanian age, though molecular evidence suggests the genus originated in the Triassic period, around 228 million years ago.
Ptilidium is a genus of liverwort, and is the only genus in family Ptilidiaceae. It includes only three species: Ptilidium californicum, Ptilidium ciliare, and Ptilidium pulcherrimum. The genus is distributed throughout the arctic and subarctic, with disjunct populations in New Zealand and Tierra del Fuego. Molecular analysis suggests that the genus has few close relatives and diverged from other leafy liverworts early in their evolution.
Petalophyllum ralfsii, the petalwort, is a liverwort of the order Fossombroniales. It is a small green bryophyte that occurs in the Mediterranean region as far east as Turkey, and along the Atlantic coast of Europe as far as northwest Scotland. It grows primarily on moist sand dunes.
Radula demissa is a species of liverwort in the family Radulaceae. It occurs in southeastern Australia and New Zealand, where it grows as an epiphyte in temperate rainforest environments.
Cladoradula perrottetii is a species of liverwort is the family Radulaceae. It is distributed across tropical and subtropical Southeast Asia, occurring in Thailand, Sumatra, Taiwan and Japan. It contains the small molecule perrottetinene, a cannabinoid, and other secondary metabolites of scientific interest including marchantin A.
Drepanolejeunea senticosa is a critically endangered species of liverwort in the family Lejeuneaceae, endemic to Cuba. The species is epiphyllous, meaning it grows on the surfaces of living leaves, and is found in subtropical/tropical moist lowland forest habitats. While male specimens have been frequently observed, the species' perianth and capsule remain undescribed.
Kuettlingeria is a genus of saxicolous (rock-dwelling), crustose lichens in the family Teloschistaceae. Species are characterized by a white or gray thallus and the presence of anthraquinones in the apothecial disc and true exciple, with the exception of Kuettlingeria diphyodes, which entirely lacks anthraquinones. First described by Italian botanist Trevisan in 1857, the genus includes 15 recognized species, although it is believed to be more diverse with additional unnamed species. These lichens are predominantly found in the Northern Hemisphere, particularly in the Mediterranean region, and grow on limestone and base-rich siliceous outcrops in sunlit conditions.
Cladoradula is a genus of liverworts in the family Radulaceae. Distinguished by its thick, brown-pigmented stems and distinctive branching pattern, it comprises seven species found primarily in tropical and temperate forest regions worldwide. Originally established as a subgenus of Radula in 1885, it was elevated to genus rank in 2022 following molecular studies that revealed it represents one of the oldest lineages within Radulaceae, having diverged during the late Permian period about 263 million years ago. The genus is characterised by its specialised stem structure, distinctive leaf arrangement, and small protective structures around its reproductive organs. Species in the genus grow on tree bark or shaded rocks from sea level to over 2,000 m (6,600 ft) in elevation.
Dactyloradula is a liverwort genus in the family Radulaceae, containing the single species Dactyloradula brunnea. The species is endemic to Japan, though a disjunct population was historically known from Oregon in the western United States. The species typically grows as an epiphyte on tree bark in temperate forests, particularly in subalpine regions, and occasionally on rock faces. First described in 1910 as a species of Radula, it was elevated to genus status in 2022 based on its distinctive morphological features and ancient evolutionary history. The genus is characterised by its bistratose stem cortex, finger-like appendages at the base of its leaf lobules, and regular production of specialised branches called amentulose (reduced-leaf) shoots. Molecular studies indicate that Dactyloradula represents one of the earliest diverging lineages within Radulaceae, having separated from other members of the family about 133 million years ago during the Early Cretaceous period.
