Research Article |
Corresponding author: Ming-Xun Ren ( renmx@hainu.edu.cn ) Academic editor: Kang Ming
© 2020 Ke Tan, Tao Lu, Ming-Xun Ren.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Tan K, Lu T, Ren M-X (2020) Gesneriaceae in China and Vietnam: Perfection of taxonomy based on comprehensive morphological and molecular evidence. In: Shui Y-M, Chen W-H, Ren M-X, Wen F, Hong X, Qiu Z-J, Wei Y-G, Kang M (Eds) Taxonomy of Gesneriaceae in China and Vietnam. PhytoKeys 157: 7-26. https://doi.org/10.3897/phytokeys.157.34032
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Based on an updated taxonomy of Gesneriaceae, the biogeography and evolution of the Asian Gesneriaceae are outlined and discussed. Most of the Asian Gesneriaceae belongs to Didymocarpoideae, except Titanotrichum was recently moved into Gesnerioideae. Most basal taxa of the Asian Gesneriaceae are found in the Indian subcontinent and Indo-China Peninsula, suggesting Didymocarpoideae might originate in these regions. Four species diversification centers were recognized, i.e. Sino-Vietnam regions, Malay Peninsula, North Borneo and Northwest Yunnan (Hengduan Mountains). The first three regions are dominated by limestone landscapes, while the Northwest Yunnan is well-known for its numerous deep gorges and high mountains. The places with at least 25% species are neoendemics (newly evolved and narrowly endemic) which were determined as evolutionary hotspots, including Hengduan Mountains, boundary areas of Yunnan-Guizhou-Guangxi in Southwest China, North Borneo, Pahang and Terengganu in Malay Peninsula, and mountainous areas in North Thailand, North Sulawesi Island. Finally, the underlying mechanisms for biogeographical patterns and species diversification of the Asian Gesneriaceae are discussed.
Didymocarpoideae, endemic, species diversification, limestone landscape, monsoon, long-distance dispersal
Gesneriaceae Rich. & Juss. ex. DC. is a middle-sized family, including about 150 genera and over 3400 species (
Based on recent molecular and morphological data,
Recently, many Asian Gesneriaceae taxa had experienced extensive revision for their systematic positions, such as Boea Commerson ex Lamarck (
In this paper, we collected the species locality data (coordinates) from GBIF (Global Biodiversity Information Facility, https://www.gbif.org/) for all the species of the Asian Gesneraiceae. The species diversity and systematic positions of all genera were determined according to the newest literatures (e.g.
Based on
I. Pantropics
I1. Tropic Asia and tropic America disjuncted: Rhynchoglossum Blume.
I2. Tropic Asia to tropic Australia: Boea Comm. ex Lam., Cyrtandra J. R. Forster & G. Forster, Stauranthera Bentham, Rhynchotechum Blume.
I3. Tropic Asia to tropic Africa: Epithema Blume.
II. Tropical and subtropical Asia
II1. Widespread in tropical and subtropical Asia: Aeschynanthus Jack, Paraboea (C. B. Clarke) Ridley, Dorcoceras Bunge, Codonoboea Ridl., Didymostigma W. T. Wang, Henckelia Spreng., Didymocarpus Wallich.
II2. East India to Java: Boeica C. B. Clarke, Leptoboea Benth., Beccarinda Bentham, Microchirita, Middletonia D.J. Middleton.
II3. Indo-China Peninsula: Tetraphyllum C.B.Clarke, Deinostigma W.T.Wang & Z.Y.Li, Damrongia Kerr ex Craib, Kaisupeea B.L. Burtt, Tribounia D.J. Middleton ex M. Möller, Billolivia, Chayamaritia, Rachunia D.J. Middleton.
II4. North of Indo-China Peninsula: Pseudochirita W. T. Wang, Anna Pellegrin.
II5. Subtropic Asia (Southwest and South China): Primulina Hance, Whytockia W. W. Smith, Hemiboea C. B. Clarke, Glabrella M. Möller & W. H. Chen, Gyrocheilos W. T. Wang, Raphiocarpus Chun, Petrocodon Hance, Allostigma W. T. Wang, Allocheilos W. T. Wang, Gyrogyne W. T. Wang, Litostigma Y.G. Wei, Fang Wen & M. Möller.
II6. Malay Peninsula to Southwest China: Ornithoboea Parish ex C. B. Clarke.
II7. Hainan Island: Cathayanthe W. Y. Chun, Metapetrocosmea W. T. Wang.
II8. Sri Lanka and India: Championia Gardn., Jerdonia Wight.
II9. Malay Peninsula: Orchadocarpa Ridl., Emarhendia R. Kiew, A. Weber & B.L. Burtt, Senyumia R. Kiew, A. Weber & B.L. Burtt, Somrania D.J. Middleton, Spelaeanthus R. Kiew, A. Weber & B.L. Burtt.
II10. Malay Archipelago: Agalmyla Blume, Monophyllaea R. Br., Loxocarpus R. Br., Loxonia Jack, Didissandra C.B. Clarke, Liebigia, Ridleyandra A. Weber & B.L. Burtt.
II11. Borneo Island: Hexatheca C.B. Clarke.
III. North Temperate
III1. Widespread in East Asia: Oreocharis Bentham.
III2. Sino-Himalaya: Corallodiscus Batalin, Loxostigma C.B. Clarke.
III3. Sino-Japan: Conandron Sieb. & Zucc., Titanotrichum Solereder.
III4. Hengduan Mountains to Yunnan Plateau: Rhabdothamnopsis Hemsl.
III5. Hengduan Mountains to Central China: Briggsiopsis K. Y. Pan, Petrocosmea Oliver.
III6. Himalaya: Platystemma Wallich.
Tropical and subtropical Asia are the distribution centers of the subfamily Didymocarpoideae, harbouring 85% genus and more than 90% species of Didymocarpoideae. Indo-China Peninsula and Southwest China (Figs
Our data recognized four species diversification centers (places with highest values of species density), i.e. Sino-Vietnam Region including boundary areas of Guizhou-Yunnan-Guangxi in Southwest China, Northwest Yunnan (Hengduan Mountains), Malay Peninsula and North Borneo (Fig.
Indo-China Peninsula turned out to be an extraordinary diversification center, harbouring several endemic genera Tribounia, Billolivia, Chayamaritia (Fig.
Species distributions pattern of the Asian Gesneriaceae. Black circles indicate diversification centers with highest species richness and the red grids are the evolutionary hotspots (at least 25% species are neoendemics). The species distribution information is obtained from http://www.gbif.org. The map was drawn using DIVA-GIS7.5.
Genera phylogeny with geographical distribution pattern of the Asian Gesneriaceae. The number in the brackets is the species diversity of the genus. Phylogeny tree was redrawn based on
We determined places where at least 25% species are local endemics as ‘evolutionary hotspots’. Six evolutionary hotspots were identified, i.e. Northwest Yunnan (Hengduan Mountains), boundary areas of Yunnan-Guizhou-Guangxi in Southwest China, mountains in North Thailand, Malay Peninsula, North Borneo, and North Sulawesi (Fig.
The geography of these six evolutionary hotspots was the most complex area in tectonic history, formed by the interaction of Indian, Eurasian, Australian and Pacific Plates (
An up-to-date phylogeny indicated that Didymocarpoideae and Gesnerioideae probably separated at about 74 Ma (
The new position of Titanotrichum in the Gesnerioideae (
The alternative hypothesis is that the Asian Gesneriaceae might follow the ‘Malpighiaceae Route’ via the ‘North Atlantic land bridge’ to Eurasia (
According to
Unifoliate growth form strongly suggests that growth form positively influences speciation rate (
Normally, most Gesneriaceae species exhibiting zygomorphic flowers are thought to be more specialised in pollination adaptation, since it restricts pollinator behaviour and can therefore increase pollination efficiency (
Most Asian Gesneriaceae has the fused anthers, normally anthers are united by pairs, such as Loxostigma and Anna (
There is a highly specialized pollination mechanism in the Asian Gesneriaceae, i.e. mirror-image flowers (
In angiosperms, fruits significantly increase adaptive ability to withstand harsh environments and facilitate seed dispersal (
In Cyrtandra and Rhynchotechum, soft-fleshy (a true berry) fruits facilitate their colonisation throughout the Southeast Asia islands and nearby Pacific islands via bird dispersals (
Compared to other regions, Asia is mostly dominated by the monsoon climate. There are three main types of summer monsoons in Asia, i.e. East Asia Monsoon, South Asia Monsoon and North-west Pacific Ocean Monsoon (
Many studies had pointed out that microhabitat isolation caused by various landscapes such as limestone is the main factor for speciation in the Asian Gesneriaceae (
Southwest China has the largest continuous limestone areas in the world, which includes Guizhou, Yunnan, Guangxi provinces and the Sino-Vietnam region (
Northwest Yunnan (Hengduan Mountains), located at the eastern fringe of the Tibetan Plateau, is widely recognised as a globally important biodiversity hotspot (
In conclusion, we have discussed the biogeographic and diversification patterns of the Asian Gesneriaceae, along with underlying mechanisms of the family’s dispersal, adaptation and evolution. The family is still undergoing quick diversification and is awaiting further detailed studies not only about ecological adaptations but also evo-devo examinations on relationships between micro- and macro-evolution. Molecular biogeographic studies on the typical pantropic taxa using updated techniques such as sequenced restriction-site associated DNA (
Gernus | Distribution | Habitat | Species number | Taxonomic status | Reference |
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Subfamily Gesnerioideae | |||||
Tribe Titanotricheae | |||||
Titanotrichum | E China (Fujian and Taiwan) and Japan | Shaded areas in valleys; altitude 100–1200 m. | 1 | Placed in subfam. Gesnerioideae |
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Subfamily Didymocarpoideae | |||||
Tribe Epithemateae | |||||
Epithema | Central tropical Africa, India, Sri Lanka, Nepal, southern China and through Southeast Asia and Malesia to the Solomon Islands. | Shaded limestone rocks or caves in valleys. | 20 | No change at genus level |
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Gyrogyne | S China (Bose Xian, W Guangxi) | Shaded waysides in hilly regions at low elevations. | 1 | Position in Epithemateae-Loxoniinae uncertain | |
Loxonia | Southeast Asia (Sumatra, Malay Peninsula, Borneo, Java) | Damp places and humid rocks in deep shade. | 3 | No change | |
Monophyllaea | Throughout Sumatra to New Guinea and from S Thailand and Luzon to Java | Limestone rocks, in shady forests, at cave entrances and below rocks. | >40 | No change |
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Rhynchoglossum | From India and S China to New Guinea, but one species distributed in Central America (Mexico, Colombia, Venezuela) | Wet and shady (preferably limestone) rocks, in forest or open, shady places; usually in the lowlands. | 16 | No change | |
Stauranthera | from NE India and S China throughout Malaysia to New Guinea | Wet rocks and damp places in lowland rain forest. | 7 | No change | |
Whytockia | S China (Sichuan, Guangxi, Hunan, Hubei, Guizhou, Yunnan and Taiwan) | Shaded and moist areas in valleys, shaded streamside rocks and stream banks, altitude 500–2200 m. | 8 | No change | |
Tribe Trichosporeae | |||||
Aeschynanthus | From S China, N & S India throughout Malesia to New Guinea and the Solomon Islands | Epiphytically on trees (rarely on rocks or bare soil), lowland or montane rain forest. | ~185 | Emended by inclusion of Micraeschynanthus | |
Agalmyla | Malaysia (Sumatra, Malay Peninsula, Borneo, Java, Sulawesi, New Guinea) | Lowland and montane rainforest, mostly climbers. | 96 | No change | |
Allocheilos | S China (Guizhou, E Yunnan) | Rocks in limestone hills, altitude ca. 1400 m. | 2 | No change | |
Allostigma | S China | Limestone pavements; altitude ca. 200 m. | 1 | No change | |
Anna | China, N Vietnam | Grassy slopes or forests, rock crevices in limestone hills. | 4 | No change | |
Beccarinda | NE India, Burma, S China, Vietnam, Sumatra | Probably growing on humid rocks. | 8 | No change | |
Billolivia | E Vietnam (Lam Dong) | Submontane tropical evergreen closed forest at 1550 m alt. | 7 | Re-established for five species of Cyrtandra |
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Boea | Eastern Indonesia, Papua New Guinea, the Solomon Islands and Queensland (Australia) | Limestone, moorstone and argillite montane cliffs or shady places under the forest, altitude 100–3300 m. | 11 | Redefined; Chinese spp. now in Dorcoceras and Damrongia |
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Boeica | Bhutan, S China, N & NE India, Myanmar, N Vietnam, NW Malaya | Shady and damp places and on humid rocks in forests, altitude 200–1400 m. | 14 | No change |
|
Briggsiopsis | S China (C & S Sichuan, NE Yunnan, Guizhou) | Forests, at stream sides and on rocks in shady places, altitude 250–1500 m. | 1 | No change | |
Cathayanthe | S China (Hainan) | Rocks, in wet valleys and ravines; altitude ca. 1800 m. | 1 | No change | |
Championia | Sri Lanka | Undisturbed forest, in shady places and loose soil along stream beds. | 1 | No change | |
Chayamaritia | Central and eastern Thailand, Laos. | Evergreen and submontane forest in deep shade at 150–1200 m altitude. | 2 | Genus recently established |
|
Codonoboea | S Thailand and throughout Malesia, S Japan, E China and Taiwan | Primary forest granite, sandstone and quartz derived soils or rocks. | 120 | New combination for particular species of Henckelia and Loxocarpus |
|
Conandron | E China, Taiwan region of China, S Japan | Humid and wet rocks in forests, altitude 500–1300 m. | 1 | No change | |
Corallodiscus | Bhutan, China, N & NE India, Nepal, Thailand | Rocks and rock crevices within forests or above the forest line, from 700 to nearly 5000 m. | 5 | No change | |
Cyrtandra | Nicobar Islands and S Thailand through Malesia include Taiwan region of China and the S Pacific to the Hawaiian Islands | Lowland and montane rain forests. | >800 | No change | |
Damrongia | China to Sumatra | Limestone rocks, usually in shade. | 11 | Re-established for particular species of erstwhile Chirita; inclusion of Boea clarkeana and the Asian species described in Streptocarpus |
|
Deinostigma | Southern China and Vietnam. | Forests rocks and along trails and roadsides in forested areas; altitude 650–1200 m. | 7 | Expanded to included several species previously ascribed to Primulina |
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Didissandra | W Malesia (Sumatra, Malay Peninsula, Borneo, Java) | Lowland and montane rain forests. | 8 | No change | |
Didymocarpus | From N and NE India, Nepal and S China southwards to the Malay Peninsula and N Sumatra | Damp (usually acid) rocks or earth banks, in forest or above the forest line, altitude (rarely) sea level to 3500 m. | 98 | Some spp. transferred to Petrocodon |
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Didymostigma | SE China (Guangdong, Fujian, Guangxi) & Vietnam | Forests rocks and along trails and roadsides in forested areas; altitude 650–1200 m. | 3 | No change | |
Dorcoceras | China, Thailand, Cambodia, Vietnam, Philippines and Indonesia | Shady and damp rocks along trails and roadsides in forests; 100–1500 m. | 4 | Re-established for particular (non-Australasian) species of Boea |
|
Emarhendia | Malay Peninsula | Damp limestone rocks, especially at cave entrances. | 1 | No change | |
Glabrella | S China, Taiwan region of China | Forests damp rocks and crevices of rocks; 600-1800 m. | 3 | New genus estblished for 3 spp. of Briggsia not to be included in Oreocharis or Loxostigma |
|
Gyrocheilos | S China (Guangxi, Guangdong, SE Guizhou), Vietnam | Forests wet places, in valleys and on rocks beside streams; altitude 400–1600m. | 5 | No change | |
Hemiboea | C & S China, Taiwan region of China, N Vietnam, S Japan, NE India | Forests and at forest margins rock crevices by streams and wet, shady places in karst regions; altitude 80–2500 m. | 34 | Inclusion of Metabriggsia (2 spp.) |
|
Henckelia | India, S China, Indo-China Peninsula, Malay Peninsula | Acidic soils and rocks but not on limestone. | ~60 | Redefined to include Chirita p. p. (excl. Microchirita and Primulina) and Hemiboepsis, and to exclude Codonoboea |
|
Hexatheca | Borneo (W Kalimantan, Sarawak to Sabah) | Sandstone or limestone rocks. | 4 | No change | |
Jerdonia | India (Nilghiri and Anamally Hills) | Rocks in mountains | 1 | No change | |
Kaisupeea | Myanmar, Thailand, S Laos | Wet rocks and rocks crevices along streams and waterfalls | 3 | No change | |
Leptoboea | Bhutan, N and NE India, S China (Yunnan), Myanmar, Thailand | Hills and mountains | 2 | No change | |
Liebigia | Sumatra, Java and Bali | Forest plants, also in disturbed forest, open places and forest margins, river banks etc.; probably growing in acid soil (limestone not recorded, but ecological information generally scanty) | 12 | Raised from Chirita sect. Liebigia to generic rank |
|
Litostigma | China (Guizhou, Yunnan) | Wet limestone rocks and at the entrance to caves. | 2 | Genus recently established |
|
Loxocarpus | S Thailand and E Malesia | Primary forests, often on sloping ground, river banks or on damp rocks. | 20 | New combinations |
|
Loxostigma | S China (Sichuan, Yunnan, Guizhou, Guangxi), N Vietnam | Damp, mossy rocks or on tree trunks in forests | 11 | Recently inclusion of caulescent Briggsia species |
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Lysionotus | From N India and Nepal eastwards through N Thailand, N Vietnam and S China to S Japan | Epiphytically on trees in forest or on damp mossy rocks; 300–3100 m. | 29 | No change | |
Metapetrocosmea | S China (Hainan) | Forests and stream sides, altitude 300–700 m. | 1 | No change | |
Microchirita | From the Western Ghats of India to the foothills of the Himalayas, through continental SE Asia to Sumatra, Borneo and Java | Wet, light to moderately shady places at cliff bases, on cliff walls in crevices and cracks, or at cave entrances. | 37 | Raised from Chirita sect. Microchirita to generic rank |
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Middletonia | India, Bangladesh, Bhutan, China, Burma, Thailand, Laos, Cambodia, Vietnam, Malaysia | Limestone or granite | 5 | Genus recently established for four species of Paraboea |
|
Orchadocarpa | Malay Peninsula (Main Range) | Montane forests, on acid soil. | 1 | No change | |
Oreocharis | China, Thailand, Vietnam, Myanmar, Bhutan, NE India, Japan | Shady and damp rocks by streams, in valleys or in forests on slopes or cliffs, dry shaded rocks, altitude 200–3600 m. | >120 | Expanded to include Ancylostemon, Bournea, Briggsia, Dayaoshania, Deinocheilos, Isometrum, Opithandra, Paraisometrum, Thamnocharis and Tremacron; Inclusion offurther ten spp. of Briggsia |
|
Ornithoboea | From S China and Vietnam southwards to N Peninsular Malaysia | Rocks, in shaded, humid places; some (possibly all) species confined to limestone. | 16 | No change |
|
Paraboea | Bhutan, China, Indonesia, Malaysia, Myanmar, Philippines, Thailand, Vietnam | Usually growing on limestone (rarely quartzitic) rocks, in forest or sun-exposed places, altitude 100–3200 m. | 141 | Expanded by inclusion of Phylloboea and Trisepalum; removal of four species and placement in the new genus Middletonia |
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Petrocodon | China, N Vietnam, NE Thailand | Shady places on rocks cliffs and rocks crevices of limestone hills or in broad-leaved evergreen forests; altitude sea level to 3500 m. | 33 | Expanded to include Calcareoboea, Didymocarpus, Dolicholoma, Lagarosolen, Paralagarosolen, Tengia and Wentsaiboea p. p. (exclude type) |
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Petrocosmea | NE India, S China, Myanmar, Thailand, S Vietnam | Damp rocks and shaded cliffs in forest and above the forest line, altitude 500–3100 m. | 49 | No change | |
Platystemma | Nepal, Bhutan, N India, SW China | Shady and damp rocks in valleys or dry cliffs, altitude 2300–3200 m. | 1 | No change | |
Primulina | Essentially southern half of China and Vietnam | Limestone | >190 | Enormous expansion of the previously monotypic genus by inclusion of Chirita sect. Gibbosaccus, Chiritopsis, Deltocheilos, and Wentsaiboea |
|
Pseudochirita | S China (C & W Guangxi), Vietnam | Forests on limestone hills. | 1 | No change | |
Rachunia | Thailand, Kanchanaburi province, Thong Pha Phum district, Ban E Tong, near the Thai-Myanmar border at 900 m. | Moist evergreen forest on a slope in shade. | 1 | Genus recently established |
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Raphiocarpus | S China and N & C Vietnam | Montane regions, in shady and damp places under forests, on slopes near streams or in rock crevices. | 14 | No change since |
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Rhabdothamnopsis | S China | Dense forests, at streamsides in forested areas and in thickets along roadsides, altitude 1600–2200(–4600) m. | 1 | No change | |
Rhynchotechum | NE India, Nepal, Bhutan, SW & S China, SE Asia and Malesia to New Guinea | Under broad-leaved forest in valley, shady places near the stream, on the rocks, distributed from coast to 2200 m. | 16 | No change | |
Ridleyandra | Malay Peninsula and Borneo | Lowland and (more frequently) montane rain forests. | 31 | No change |
|
Senyumia | Malay Peninsula (Pahang: Gunung Senyum and adjacent localities) | Rock faces in damp limestone caves | 1 | No change | |
Somrania | Peninsular Thailand | limestone | 2 | Genus recently established |
|
Spelaeanthus | Malay Peninsula (Pahang), Batu Luas | Damp rock faces, especially at the entrance to limestone caves. | 1 | No change | |
Tetraphyllum | NE India, Bangladesh, Myanmar, Thailand | Damp rocks in forest | 3 | No change | |
Tribounia | Thailand | Crevices of karst limestone in deciduous forest. | 2 | Genus recently established |
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Financial support was provided by the Innovative Team Program of Hainan Natural Science Foundation (2018CXTD334), National Natural Science Foundation of China (31670230 and 41871041) and the Postgraduate Innovative Grant of Hainan Province (Hyb2016-06).