We document the discovery of two new species of Hoya from Sulawesi, Indonesia, H. sulawesiana S.R... more We document the discovery of two new species of Hoya from Sulawesi, Indonesia, H. sulawesiana S.Rahayu & Rodda and Hoya surisana Rodda & S.Rahayu. Hoya sulawesiana is similar to Hoya isabelchanae Rodda & Simonsson in flower morphology because both species have very pubescent globose corolla but they can be separated based on leaf morphology and corolla indumentum type. Hoya surisana is very unusual because its flowers display a combination of large calyx lobes, a white, pubescent, campanulate corolla, and dark purple corona lobes so far not observed in any other species of the genus.
Heterostemma brownii is reported as a new record for the floras of Laos and Thailand. A lectotype... more Heterostemma brownii is reported as a new record for the floras of Laos and Thailand. A lectotype is also designated for the name Heterostemma brownii. A description based on Thai and Lao collections, photographs and notes are provided.
Статья содержит сведения о 33 новых и редких видах рода Hoya, полученные в ходе полевых работ, пр... more Статья содержит сведения о 33 новых и редких видах рода Hoya, полученные в ходе полевых работ, проводившихся на протяжении 2012–2017 гг. в восточном Индокитае, включающем территорию Камбоджи, Лаоса и Вьетнама. Полученные результаты включают иллюстрированные описания 3 видов, новых для науки, а также 24 видов, новых для флор изучаемых стран. С учетом этих данных флора восточного Индокитая насчитывает как минимум 45 видов рода, произрастание восьми из которых задокументировано для Камбоджи, 21 – для Лаоса и 40 – для Вьетнама. Два новых для науки вида описаны из Вьетнама (H. crassipetiolataи H. nutans) и один – из Лаоса (H. uniflora). 18 видов впервые указываются для флоры Вьетнама (H. arnottiana, H. burmanica, H. chinghungensis, H. erythrina, H. erythrostemma, H. fungii, H. griffithii, H. hainanensis, H. lanceolata, H. linearis, H. loyceandrewsiana, H. mengtzeensis, H. nummularioides, H. pachyclada, H. pandurata, H. parviflora, H. revolubilis, H. vaccinioides), 9 – для флоры Лаоса (H....
Blumea - Biodiversity, Evolution and Biogeography of Plants, 2021
We describe a new Hoya species from Central Kalimantan, H. buntokensis, and a new subspecies of H... more We describe a new Hoya species from Central Kalimantan, H. buntokensis, and a new subspecies of H. wallichii from West Kalimantan, Hoya wallichii subsp. tenebrosa. Hoya buntokensis is part of a group of four species that form specialised leaf structures harbouring ants (here defined as megadomatia), and it is most similar to H. undulata. Hoya buntokensis differs from H. undulata in lamina margin (flat vs undulate); shape of corona lobes outer processes (fan shaped vs elliptic), and in the pollinarium morphology (corpusculum larger than pollinia vs corpusculum smaller than pollinia). Both H. wallichii subsp. wallichii and H. wallichii subsp. tenebrosa are slender plants with ovate to oblong, thinly coriaceous glabrous leaves, slender peduncles with 1 or 2 flowers open at a time, and broadly campanulate corollas. Hoya wallichii subsp. tenebrosa differs from H. wallichii subsp. wallichii in corolla colour (dark purple with a paler edge vs white-cream), corona lobe shape and surface (br...
Hoya occultata S. Rahayu & Rodda sp. nova (Apocynaceae, Asclepiadoideae) is described from Su... more Hoya occultata S. Rahayu & Rodda sp. nova (Apocynaceae, Asclepiadoideae) is described from Sulawesi. It is the second species of Hoya from Sulawesi that has a shrubby habit. It resembles H. irisiae, an endemic of the Philippines, also a shrubby species with similar white-yellow flowers and a campanulate-urceolate corolla. The two species, however, differ in peduncle length, corolla and corona size as well as corolla, corona and pollinarium shape.
Types of all Hoya species occurring in Borneo and their synonyms are indicated and clarified. For... more Types of all Hoya species occurring in Borneo and their synonyms are indicated and clarified. Forty-six lectotypes, nine neotypes and five epitypes are designated.
All names in Heterostemma and their known synonyms are listed. Lectotypes are designated for 33 n... more All names in Heterostemma and their known synonyms are listed. Lectotypes are designated for 33 names and a neotype is designated for Stapelia quadrangula. Dittoceras is synonymised with Heterostemma and three new combinations are validated.
A new species of Hoya R.Br. from Mindanao (Philippines), Hoya migueldavidii Cabactulan, Rodda & P... more A new species of Hoya R.Br. from Mindanao (Philippines), Hoya migueldavidii Cabactulan, Rodda & Pimentel, is described and illustrated. It is a member of Hoya section Acanthostemma (Blume) Kloppenb. that is particularly speciose in the Philippines. It is compared with the similar Hoya loheri Kloppenb, also endemic of the Philippines, from which it differs in indumentum of the vegetative parts (pubescent vs. glabrous), the shape of the corolla (almost spherical vs. partly flattened) and the type of gynostegium (not stipitate vs. stipitate)
In this paper we document the discovery of a new Hoya species from Borneo, H. undulata S.Rahayu &... more In this paper we document the discovery of a new Hoya species from Borneo, H. undulata S.Rahayu & Rodda. The leaves of the new species form domatia, specialised structures harbouring ants, previously only observed in Hoya mitrata Kerr and H. darwinii Loher. The corona is unique among Bornean Hoya species as its lobes develop two lateral hooked appendages, also present in H. griffithii Hook.f, a species from mainland Asia. A lectotype for Hoya darwinii is also selected.
We report the discovery of Dischidia acutifolia Maingay ex Hook.f., a new record for the Singapor... more We report the discovery of Dischidia acutifolia Maingay ex Hook.f., a new record for the Singapore flora. The species is only known from a single locality in Sungei Buloh Wetland Reserve and is therefore considered Critically Endangered in Singapore. A lectotype for the name is selected.
Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam is describe... more Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam is described, illustrated and compared with its five congeners. Jasminanthes xuanlienensis differs distinctly from congeners by the longer peduncles (14-18 cm vs. 4 cm at most in J. pilosa and J. saxatilis, salmon-pink color of the inner corolla lobes (white or greenish in the other species), and corolla tube length (12.0-14.5 mm vs. shorter or longer in congeners).
Two new Hoya R.Br. species from Borneo are described and illustrated. The first, Hoya ruthiae Rod... more Two new Hoya R.Br. species from Borneo are described and illustrated. The first, Hoya ruthiae Rodda was collected in Sabah on Bukit Baturong, a limestone outcrop. It is one of the few species in the genus to have clear exudate. It is compared with the morphologically related Hoya uncinata Teijsm. and Binn. The other, Hoya bakoensis Rodda, was collected in the kerangas forests of Bako National Park. It belongs to Hoya section Acanthostemma (Bl.) Kloppenb., a section with numerous members in the Philippines but under-represented in Borneo.
Blumea - Biodiversity, Evolution and Biogeography of Plants, 2011
A new species from kerangas heath forest of Brunei, Borneo, Hoya wongii, is here described and il... more A new species from kerangas heath forest of Brunei, Borneo, Hoya wongii, is here described and illustrated. This species differs from the previously described species of Hoya in having a corona with inflated outer processes and laterally compressed and erect inner processes, ending in two bidentate membranaceous appendages. The corona is inserted above a pale yellow campanulate corolla. We discuss morphological affinities between the new species and other campanulate flowered species of Hoya.
We compared the nutritional modes and habitats of orchids (e.g., autotrophic, partially or fully ... more We compared the nutritional modes and habitats of orchids (e.g., autotrophic, partially or fully mycoheterotrophic) of the Mediterranean region and adjacent islands of Macaronesia. We hypothesized that ecological factors (e.g., relative light availability, surrounding vegetation) determine the nutritional modes of orchids and thus impose restrictions upon orchid distribution. Covering habitats from dark forests to open sites, orchid samples of 35 species from 14 genera were collected from 20 locations in the Mediterranean and Macaronesia to test for mycoheterotrophy. Mycorrhizal fungi were identified via molecular analyses, and stable isotope analyses were applied to test whether organic nutrients are gained from the fungal associates. Our results show that orchids with partial or full mycoheterotrophy among the investigated species are found exclusively in Neottieae thriving in light-limited forests. Neottioid orchids are missing in Macaronesia, possibly because mycoheterotrophy is constrained by the lack of suitable ectomycorrhizal fungi. Furthermore, most adult orchids of open habitats in the Mediterranean and Macaronesia show weak or no N gains from fungi and no C gain through mycoheterotrophy. Instead isotope signatures of some of these species indicate net plant-to-fungus C transfer.
The genus Hoya is highly diverse and many of its species are popular ornamental plants. However, ... more The genus Hoya is highly diverse and many of its species are popular ornamental plants. However, the relationships between Hoya and related genera (the Hoya group) are not fully resolved. In this study, we report 20 newly sequenced plastomes of species in the Hoya group. The complete plastomes vary in length from 175,405 to 178,525 bp while the LSCs vary from 90,248 to 92,364 bp and the complete SSCs vary from 2,285 to 2,304 bp, making the SSC in the Hoya group one of the shortest known in the angiosperms. The plastome structure in the Hoya group is characterised by a massive increase in the size of the inverted repeats as compared to the outgroups. In all ingroup species, the IR/SSC boundary moved from ycf1 to ndhF while this was not observed in outgroup taxa, making it a synapomorphy for the Hoya group. We have also assembled the mitogenome of Hoya lithophytica, which, at 718,734 bp, is the longest reported in the family. The phylogenetic analysis using exons from 42 taxa in the H...
Heterostemma menghaiense is reported as a new record for the flora of Laos and Thailand. A descri... more Heterostemma menghaiense is reported as a new record for the flora of Laos and Thailand. A description based on Thai and Lao collections, photographs and notes are provided.
The list of the species of Hoya R.Br. occurring on the Indonesian island of Sumatra is updated an... more The list of the species of Hoya R.Br. occurring on the Indonesian island of Sumatra is updated and the type citation is clarified. Sixteen taxa are added to the latest checklist. Hoya danumensis subsp. amarii S.Rahayu & Rodda subsp. nov., H. rigidifolia S.Rahayu & Rodda sp. nov., H. solokensis S.Rahayu & Rodda sp. nov., and H. sumatrana S.Rahayu & Rodda sp. nov. are newly described. Hoya parviflora Wight, H. parvifolia Schltr., and H. purpureofusca Hook. are lectotypified.
We document the discovery of two new species of Hoya from Sulawesi, Indonesia, H. sulawesiana S.R... more We document the discovery of two new species of Hoya from Sulawesi, Indonesia, H. sulawesiana S.Rahayu & Rodda and Hoya surisana Rodda & S.Rahayu. Hoya sulawesiana is similar to Hoya isabelchanae Rodda & Simonsson in flower morphology because both species have very pubescent globose corolla but they can be separated based on leaf morphology and corolla indumentum type. Hoya surisana is very unusual because its flowers display a combination of large calyx lobes, a white, pubescent, campanulate corolla, and dark purple corona lobes so far not observed in any other species of the genus.
Heterostemma brownii is reported as a new record for the floras of Laos and Thailand. A lectotype... more Heterostemma brownii is reported as a new record for the floras of Laos and Thailand. A lectotype is also designated for the name Heterostemma brownii. A description based on Thai and Lao collections, photographs and notes are provided.
Статья содержит сведения о 33 новых и редких видах рода Hoya, полученные в ходе полевых работ, пр... more Статья содержит сведения о 33 новых и редких видах рода Hoya, полученные в ходе полевых работ, проводившихся на протяжении 2012–2017 гг. в восточном Индокитае, включающем территорию Камбоджи, Лаоса и Вьетнама. Полученные результаты включают иллюстрированные описания 3 видов, новых для науки, а также 24 видов, новых для флор изучаемых стран. С учетом этих данных флора восточного Индокитая насчитывает как минимум 45 видов рода, произрастание восьми из которых задокументировано для Камбоджи, 21 – для Лаоса и 40 – для Вьетнама. Два новых для науки вида описаны из Вьетнама (H. crassipetiolataи H. nutans) и один – из Лаоса (H. uniflora). 18 видов впервые указываются для флоры Вьетнама (H. arnottiana, H. burmanica, H. chinghungensis, H. erythrina, H. erythrostemma, H. fungii, H. griffithii, H. hainanensis, H. lanceolata, H. linearis, H. loyceandrewsiana, H. mengtzeensis, H. nummularioides, H. pachyclada, H. pandurata, H. parviflora, H. revolubilis, H. vaccinioides), 9 – для флоры Лаоса (H....
Blumea - Biodiversity, Evolution and Biogeography of Plants, 2021
We describe a new Hoya species from Central Kalimantan, H. buntokensis, and a new subspecies of H... more We describe a new Hoya species from Central Kalimantan, H. buntokensis, and a new subspecies of H. wallichii from West Kalimantan, Hoya wallichii subsp. tenebrosa. Hoya buntokensis is part of a group of four species that form specialised leaf structures harbouring ants (here defined as megadomatia), and it is most similar to H. undulata. Hoya buntokensis differs from H. undulata in lamina margin (flat vs undulate); shape of corona lobes outer processes (fan shaped vs elliptic), and in the pollinarium morphology (corpusculum larger than pollinia vs corpusculum smaller than pollinia). Both H. wallichii subsp. wallichii and H. wallichii subsp. tenebrosa are slender plants with ovate to oblong, thinly coriaceous glabrous leaves, slender peduncles with 1 or 2 flowers open at a time, and broadly campanulate corollas. Hoya wallichii subsp. tenebrosa differs from H. wallichii subsp. wallichii in corolla colour (dark purple with a paler edge vs white-cream), corona lobe shape and surface (br...
Hoya occultata S. Rahayu & Rodda sp. nova (Apocynaceae, Asclepiadoideae) is described from Su... more Hoya occultata S. Rahayu & Rodda sp. nova (Apocynaceae, Asclepiadoideae) is described from Sulawesi. It is the second species of Hoya from Sulawesi that has a shrubby habit. It resembles H. irisiae, an endemic of the Philippines, also a shrubby species with similar white-yellow flowers and a campanulate-urceolate corolla. The two species, however, differ in peduncle length, corolla and corona size as well as corolla, corona and pollinarium shape.
Types of all Hoya species occurring in Borneo and their synonyms are indicated and clarified. For... more Types of all Hoya species occurring in Borneo and their synonyms are indicated and clarified. Forty-six lectotypes, nine neotypes and five epitypes are designated.
All names in Heterostemma and their known synonyms are listed. Lectotypes are designated for 33 n... more All names in Heterostemma and their known synonyms are listed. Lectotypes are designated for 33 names and a neotype is designated for Stapelia quadrangula. Dittoceras is synonymised with Heterostemma and three new combinations are validated.
A new species of Hoya R.Br. from Mindanao (Philippines), Hoya migueldavidii Cabactulan, Rodda & P... more A new species of Hoya R.Br. from Mindanao (Philippines), Hoya migueldavidii Cabactulan, Rodda & Pimentel, is described and illustrated. It is a member of Hoya section Acanthostemma (Blume) Kloppenb. that is particularly speciose in the Philippines. It is compared with the similar Hoya loheri Kloppenb, also endemic of the Philippines, from which it differs in indumentum of the vegetative parts (pubescent vs. glabrous), the shape of the corolla (almost spherical vs. partly flattened) and the type of gynostegium (not stipitate vs. stipitate)
In this paper we document the discovery of a new Hoya species from Borneo, H. undulata S.Rahayu &... more In this paper we document the discovery of a new Hoya species from Borneo, H. undulata S.Rahayu & Rodda. The leaves of the new species form domatia, specialised structures harbouring ants, previously only observed in Hoya mitrata Kerr and H. darwinii Loher. The corona is unique among Bornean Hoya species as its lobes develop two lateral hooked appendages, also present in H. griffithii Hook.f, a species from mainland Asia. A lectotype for Hoya darwinii is also selected.
We report the discovery of Dischidia acutifolia Maingay ex Hook.f., a new record for the Singapor... more We report the discovery of Dischidia acutifolia Maingay ex Hook.f., a new record for the Singapore flora. The species is only known from a single locality in Sungei Buloh Wetland Reserve and is therefore considered Critically Endangered in Singapore. A lectotype for the name is selected.
Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam is describe... more Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam is described, illustrated and compared with its five congeners. Jasminanthes xuanlienensis differs distinctly from congeners by the longer peduncles (14-18 cm vs. 4 cm at most in J. pilosa and J. saxatilis, salmon-pink color of the inner corolla lobes (white or greenish in the other species), and corolla tube length (12.0-14.5 mm vs. shorter or longer in congeners).
Two new Hoya R.Br. species from Borneo are described and illustrated. The first, Hoya ruthiae Rod... more Two new Hoya R.Br. species from Borneo are described and illustrated. The first, Hoya ruthiae Rodda was collected in Sabah on Bukit Baturong, a limestone outcrop. It is one of the few species in the genus to have clear exudate. It is compared with the morphologically related Hoya uncinata Teijsm. and Binn. The other, Hoya bakoensis Rodda, was collected in the kerangas forests of Bako National Park. It belongs to Hoya section Acanthostemma (Bl.) Kloppenb., a section with numerous members in the Philippines but under-represented in Borneo.
Blumea - Biodiversity, Evolution and Biogeography of Plants, 2011
A new species from kerangas heath forest of Brunei, Borneo, Hoya wongii, is here described and il... more A new species from kerangas heath forest of Brunei, Borneo, Hoya wongii, is here described and illustrated. This species differs from the previously described species of Hoya in having a corona with inflated outer processes and laterally compressed and erect inner processes, ending in two bidentate membranaceous appendages. The corona is inserted above a pale yellow campanulate corolla. We discuss morphological affinities between the new species and other campanulate flowered species of Hoya.
We compared the nutritional modes and habitats of orchids (e.g., autotrophic, partially or fully ... more We compared the nutritional modes and habitats of orchids (e.g., autotrophic, partially or fully mycoheterotrophic) of the Mediterranean region and adjacent islands of Macaronesia. We hypothesized that ecological factors (e.g., relative light availability, surrounding vegetation) determine the nutritional modes of orchids and thus impose restrictions upon orchid distribution. Covering habitats from dark forests to open sites, orchid samples of 35 species from 14 genera were collected from 20 locations in the Mediterranean and Macaronesia to test for mycoheterotrophy. Mycorrhizal fungi were identified via molecular analyses, and stable isotope analyses were applied to test whether organic nutrients are gained from the fungal associates. Our results show that orchids with partial or full mycoheterotrophy among the investigated species are found exclusively in Neottieae thriving in light-limited forests. Neottioid orchids are missing in Macaronesia, possibly because mycoheterotrophy is constrained by the lack of suitable ectomycorrhizal fungi. Furthermore, most adult orchids of open habitats in the Mediterranean and Macaronesia show weak or no N gains from fungi and no C gain through mycoheterotrophy. Instead isotope signatures of some of these species indicate net plant-to-fungus C transfer.
The genus Hoya is highly diverse and many of its species are popular ornamental plants. However, ... more The genus Hoya is highly diverse and many of its species are popular ornamental plants. However, the relationships between Hoya and related genera (the Hoya group) are not fully resolved. In this study, we report 20 newly sequenced plastomes of species in the Hoya group. The complete plastomes vary in length from 175,405 to 178,525 bp while the LSCs vary from 90,248 to 92,364 bp and the complete SSCs vary from 2,285 to 2,304 bp, making the SSC in the Hoya group one of the shortest known in the angiosperms. The plastome structure in the Hoya group is characterised by a massive increase in the size of the inverted repeats as compared to the outgroups. In all ingroup species, the IR/SSC boundary moved from ycf1 to ndhF while this was not observed in outgroup taxa, making it a synapomorphy for the Hoya group. We have also assembled the mitogenome of Hoya lithophytica, which, at 718,734 bp, is the longest reported in the family. The phylogenetic analysis using exons from 42 taxa in the H...
Heterostemma menghaiense is reported as a new record for the flora of Laos and Thailand. A descri... more Heterostemma menghaiense is reported as a new record for the flora of Laos and Thailand. A description based on Thai and Lao collections, photographs and notes are provided.
The list of the species of Hoya R.Br. occurring on the Indonesian island of Sumatra is updated an... more The list of the species of Hoya R.Br. occurring on the Indonesian island of Sumatra is updated and the type citation is clarified. Sixteen taxa are added to the latest checklist. Hoya danumensis subsp. amarii S.Rahayu & Rodda subsp. nov., H. rigidifolia S.Rahayu & Rodda sp. nov., H. solokensis S.Rahayu & Rodda sp. nov., and H. sumatrana S.Rahayu & Rodda sp. nov. are newly described. Hoya parviflora Wight, H. parvifolia Schltr., and H. purpureofusca Hook. are lectotypified.
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Papers by Michele Rodda