[Botany • 2026] Rhododendron trichopetalum & R. yalaense (Ericaceae) • Two New Species, Three New Records and Taxonomic Notes of Rhododendron in Thailand

Rhododendron yalaense Tubtamat, Watthana & Suwanph.
 

 in Tubtamat, Watthana, Hodkinson et Suwanphakdee, 2026. 

DOI: doi.org/10.20531/tfb.2026.54.2.10

Photographed by M. Tubtamat and C. Suwanphakdee.

Abstract

Two new species, Rhododendron trichopetalum and R. yalaense, from Peninsular Thailand, are described and illustrated. Three new records of R. jasminiflorum, R. klossii and R. robinsonii are newly reported for Thailand, and R. klossii is herein reinstated. Lectotypifications were designated where required and an updated key to species, modified from the Flora of Thailand, is provided.

Keywords: anatomical features, Ericaceae, plant taxonomy, pollen morphology, Flora of Thailand

Rhododendron trichopetalum Tubtamat & Suwanph.
A. flowering branch; B. flowers; C. hairs on corolla tube; D. basal filament with hairs; E. anther; F. ovary; G. stigma; H. capsule.

Photographed by C. Suwanphakdee and M. Tubtamat.

Rhododendron trichopetalum Tubtamat & Suwanph., sp. nov.

This species is similar to Rhododendron javanicum subsp. teysmannii (Miq.) Argent, however, R. trichopetalum lacks hairs on lower leaf surfaces (vs sparsely hairy or glandular-verruculose in R. javanicum subsp. teysmannii), with the corolla tube being sparsely hairy outside (vs glabrous), and the larger capsule 2.3–2.5 cm long (vs 3.7–8 cm long).

Rhododendron yalaense Tubtamat, Watthana & Suwanph.
A. habit; B. scales on lower leaf surface; C. inflorescence; D. ovary; E. stigma; F. capsule.

Photographed by M. Tubtamat and C. Suwanphakdee.

Rhododendron yalaense Tubtamat, Watthana & Suwanph., sp. nov.

This new species is similar to Rhododendron rarilepidotum J.J.Sm., endemic to Indonesia, but differs by having petioles without grooves (vs with grooves in R. rarilepidotum), corolla 3.1–3.6 cm long (vs 2–2.5 cm long), pale orange with 2.1–3.0 cm long filaments (vs purplish, dark red or white, 0.9–1.0 cm long), yellow anthers (vs purplish) and cylindrical capsule (vs fusiform capsule).

Maneenuch Tubtamat, Santi Watthana, Trevor R. Hodkinson and Chalermpol Suwanphakdee. 2026. Two New Species, Three New Records and Taxonomic Notes of Rhododendron (Ericaceae) in Thailand. Thai Forest Bulletin (Botany). 54(2); 92–116. DOI: doi.org/10.20531/tfb.2026.54.2.10 [2026-08-10] 

facebook.com/BotanyKU/posts/1514419747153693 

กุหลาบฮาลา และ กุหลาบเพลิงภักดิ์: กุหลาบพันปีชนิดใหม่ของโลก

facebook.com/BotanyKU/posts/1514419747153693 

👩🏻‍💼น.ส. มณีนุช ทับทะมาตย์ นิสิตปริญญาโท ภาควิชาพฤกษศาสตร์ คณะวิทยาศาสตร์ มหาวิทยาลัยเกษตรศาสตร์ ค้นพบกุหลาบพันปี  ชนิดใหม่ของโลก 2 ชนิด 

🔬การค้นพบนี้เป็นผลงานวิจัยในระดับปริญญาโท ภายใต้การดูแลของ รศ. ดร. เฉลิมพล สุวรรณภักดี ภาควิชาพฤกษศาสตร์ คณะวิทยาศาสตร์ มหาวิทยาลัยเกษตรศาสตร์, รศ. ดร. สันติ  วัฒฐานะ สาขาวิชาชีววิทยา สำนักวิชาวิทยาศาสตร์ มหาวิทยาลัยเทคโนโลยีสุรนารี และ Prof. Dr. Trevor R. Hodkinson จากทรินิตี้คอลเลจ มหาวิทยาลัยแห่งกรุงดับลิน ประเทศไอร์แลนด์ ซึ่งตีพิมพ์เผยแพร่ในวารสาร 🌱Thai Forest Bulletin (Botany) 🌱 ซึ่งกุหลาบพันปีทั้ง 2 ชนิด ประกอบด้วย

1. Rhododendron trichopetalum Tubtamat & Suwanph. ชื่อไทย กุหลาบฮาลา พบที่จังหวัดนราธิวาส  ดอกมีสีเหลืองเข้ม กลีบดอกเป็นเอกลักษณ์ และเจริญเติบโตแบบพืชอิงอาศัยในป่าดิบชื้น ความโดดเด่นของลักษณะดอกและการปรับตัวต่อสภาพแวดล้อม ทำให้มีศักยภาพในการใช้เป็นแหล่งพันธุกรรมสำหรับการปรับปรุงพันธุ์ไม้ดอกประดับในอนาคต

2. Rhododendron yalaense Tubtamat, Watthana & Suwanph. ชื่อไทย กุหลาบเพลิงภักดิ์ พบที่จังหวัดยะลา ดอกมีสีส้มเข้ม ออกเป็นช่อค่อนข้างแน่น และเจริญเติบโตแบบพืชอิงอาศัย ด้วยลักษณะดอกที่โดดเด่นและสีสันสวยงาม จึงมีศักยภาพในการพัฒนาเป็นไม้ดอกประดับในอนาคต ควบคู่กับการอนุรักษ์ทรัพยากรพันธุกรรมของพืชพื้นถิ่นไทย

[Botany • 2026] Rhododendron jiucaipingensis (Ericaceae, subgen. Hymenanthes) • A New Species from Guizhou, China

Rhododendron jiucaipingensis Jian Xu & M. T. An, 

in Hu, Xu, An, Yu et Lu, 2026. 

韭菜坪杜鹃  ||  DOI: doi.org/10.3897/phytokeys.275.183519

Abstract

Rhododendron jiucaipingensis Jian Xu & M. T. An, sp. nov. (Ericaceae), a new species of R. subgen. Hymenanthes, subsect. Argyrophylla, from northwestern Guizhou, China, is described and illustrated. It is an evergreen shrub 1.5–3.0 m tall, characterized by green, densely white-tomentose current-year branchlets, leaves crowded at branch apices (5.5–9.5 × 2.5–4.0 cm) with 8–11 pairs of lateral veins, 10 stamens, and cylindric capsules 1.2–2.0 cm long. The new species is morphologically most similar to R. hypoglaucum and R. argyrophyllum, but it is readily distinguished by having densely white-tomentose current-year branchlets, fewer lateral veins (8–11 pairs), a double-layered white indumentum on the abaxial surfaces of young leaves, and 10 stamens. Phylogenetic analysis based on a whole-genome SNP dataset robustly resolves R. jiucaipingensis as a distinct lineage within subsect. Argyrophylla, positioned as sister to the monophyletic clade of five congeneric species with high support (SH-aLRT = 100%, UFBoot = 100%). This molecular evidence, congruent with diagnostic morphological characters, supports the recognition of R. jiucaipingensis as a species new to science.

Key words: Ericaceae, Flora of China, morphology, phylogeny, taxonomy

Rhododendron jiucaipingensis Jian Xu & M. T. An, sp. nov.
 A. Cliff habitat; B. Older branches; C. Current-year branchlet and its dense white tomentum (inset); D. Mature leaf and its short, brown tomentum on the abaxial surface (inset); E. Adaxial surface of young leaf; F. Abaxial surface of young leaf and long white glandular hairs of it (inset); G. Flowering plant; H. Anatomical diagram of the flower and leaf; I. Stamens and their white stiff hairs at the filament base (inset); J. Calyx; K. Ovary; L. Capsule and its colorless stellate hairs (inset); M. Capsule in longitudinal section (Photographs by Jian Xu)

Diagnosis. Rhododendron jiucaipingensis belongs to subgen. Hymenanthes and is similar in morphology to R. hypoglaucum and R. argyrophyllum, but can be distinguished from R. hypoglaucum by its current-year branchlets and young petioles being densely covered with indumentum (vs. glabrous), and its pedicels being densely white-villous (vs. glabrous). It further differs from R. hypoglaucum in having fewer lateral veins (8–11 pairs vs. 10–14 pairs), an ovary sparsely covered with colorless stellate hairs (vs. glabrous), and typically 7-loculed capsules (vs. 6-loculed). Compared to R. argyrophyllum, the new species is distinguished by its acuminate leaf apex (vs. obtuse), fewer stamens (10 vs. 12–15), and the presence of colorless stellate hairs on the ovary (vs. white short tomentum). Additionally, R. jiucaipingensis is characterized by its restricted cliff habitat at higher elevations (2,400–2,700 m).

Etymology. The specific epithet jiucaipingensis refers to the type locality, Xingfa Township (Jiucaiping), Hezhang County, Bijie City, Guizhou, China.

Vernacular name. The Chinese name is jiǔ cài píng dù juān (韭菜坪杜鹃).

Hong-Fen Hu, Jian Xu, Ming-Tai An, Jiang-Hong Yu, Xing Lu. 2026. Rhododendron jiucaipingensis (Ericaceae), A New Species from Guizhou, China. PhytoKeys 275: 15-26. DOI: doi.org/10.3897/phytokeys.275.183519 [19 May 2026]

[Botany • 2026] Rhododendron luohanbaense (Ericaceae, subgen. Hymenanthes) • A New Species from northeast Yunnan, China

 

Rhododendron luohanbaense Y.L.Zhao & D.T.Liu, 

 in Zhao, Gu, Liao, Zhang, Li, Xie, Wang, Ma, Mao et Liu, 2026. 

罗汉坝杜鹃  ||  DOI: doi.org/10.3897/phytokeys.273.182747

Abstract

Rhododendron luohanbaense, a new species of Ericaceae, is described from Zhaotong City in northeastern Yunnan Province, China. Morphologically, it is most similar to both R. pachytrichum and R. maculiferum and can be classified into the subgen. Hymenanthes sect. Pontica subsect. Maculifera. However, it can be easily distinguished by markedly smaller and narrower leaves with acuminate apex, abaxial midribs densely covered with woolly indumentum, yellowish-green corollas speckled with green or purple dots, inflorescences bearing up to 7 flowers, flowers with ovary densely pilose, capsule densely brown setose. Phylogenomic evidence, based on a coalescent-based species tree reconstructed from 5358 single-copy nuclear orthologous genes, also supports recognition of the new taxon.

Key words: Ericaceae, new taxon, nuclear orthologous genes, phylogeny

Rhododendron luohanbaense Y.L.Zhao & D.T.Liu, sp. nov.
 A. Leaf; B. Leaf, abaxial midrib; C. Flowering branch; D. Dissection of flower; E. Ovary; F. Opened capsule; G. Habitat; H. Stem.

Rhododendron luohanbaense (A, D, G, J), R. pachytrichum (B, E, H, K) and R. maculiferum (C, F, I, L).
A–C. Leafy branches; D–F. Abaxial midrib of leaves; G–I. Flowering branch; J–L. Capsule.

Rhododendron luohanbaense Y.L.Zhao & D.T.Liu, sp. nov.

Etymology. The specific epithet derives from the Luohanba, the subzone of the Yunnan Wumengshan National Nature Reserve where the holotype was collected; Chinese mandarin: luó hàn bà dù juān (罗汉坝杜鹃).

 Yong-Li Zhao, Chao-Shan Gu, Zheng-Hang Liao, Jing-Li Zhang, Wei Li, Zhu-Fang Xie, Fei Wang, Yong-Peng Ma, Xing-Xing Mao and De-Tuan Liu. 2026. Rhododendron luohanbaense (Ericaceae), A New Species from northeast Yunnan, China. PhytoKeys 273: 299-308. DOI: doi.org/10.3897/phytokeys.273.182747 [23 Apr 2026]

[Botany • 2026] Rhododendron yombuwurii (Ericaceae, subgen. Vireya) • A New orange-flowered Species from Central Sulawesi, Indonesia

  

Rhododendron yombuwurii Hutabarat, Bandjolu & Zulfadli,  

in Hutabarat, Zulfadli, Bandjolu, Basrul, Hariri, Senatama et Larekeng, 2026.

taiwania.ntu.edu.tw/abstract/2170  

Abstract

A new species of Rhododendron subgenus Vireya from Central Sulawesi, Rhododendron yombuwurii, is described. The species is known from material originating from the Tokorondo Range, northwest of Lake Poso, and is currently cultivated at a lower elevation near Saluopa Waterfall, where it grows epiphytically and produces small, bright orange flowers. We provide a detailed morphological description, comparative microscopic observations, notes on distribution, habitat and ecology, and a preliminary conservation assessment. Phylogenetic analyses based on the nuclear ribosomal ITS region support the placement of the species within subgenus Vireya and its distinction from morphologically similar taxa.

Keyword: Flora, Malesia, Mountain flora, Poso, Rhododendron celebicum, Schistanthe, Tokorondo, Wallacea

A. Rhododendron yombuwurii thriving and flowering as an epiphyte beneath the canopy of a small tree in Tentena, Central Sulawesi; B. The fresh material of the type specimen PWH1635; C. Flower bud of R. yombuwurii.

(Photographed by P.W.K. Hutabarat)

Morphology of Rhododendron yombuwurii Hutabarat, Bandjolu & Zulfadli, sp. nov.
 A. flowering stem; B. Semi–erect inflorescence; C. Flower bud; D. Glabrescent adaxial leaf; E. Scaly petiole; F. Scaly abaxial leaf; G. Scales on abaxial leaf; H. Narrow funnel–shaped corolla; I. Corolla lobes and stamen position; J. Corolla (inside); K. Androecium and gynoecium; L. Stamen; M. Gynoecium; N. Immature fruit; O. Laxly scaly ovary

 (Photographed by Zulfadli)

Rhododendron yombuwurii Hutabarat, Bandjolu & Zulfadli, sp. nov.

Diagnosis: Rhododendron yombuwurii is most closely allied to R. celebicum (Blume) DC. (de Candolle, 1839), and shows affinity to R. impressopunctatum J.J.Sm. (Smith, 1932), and R. vidalii subsp. brachystemon Argent (Argent, 2003). It differs from R. celebicum by its raised midrib and lateral veins (vs. slightly impressed), semi-erect to horizontal inflorescences (vs. pendulous), glabrous calyx externally (vs. densely scaly), and much smaller orange corolla, 17–22 × 12–16 mm (vs. 35–46 × 20–25 mm, pink to red). From R. impressopunctatum it differs in having smaller leaves, fewer-flowered inflorescences, smaller orange corollas, and filaments clustered at the corolla mouth rather than exserted. The species further differs from R. vidalii subsp. brachystemon by its scaly young twigs becoming glabrescent, longer leaves with raised veins, glabrous calyx externally, smaller orange corolla, and a sparsely scaly to nearly glabrescent ovary. Additional distinguishing characters are summarized in Table 1. ...

A. Type locality of Rhododendron yombuwurii in the Tokorondo Range, Poso Regency, Central Sulawesi. The red dot marks Saluopa Waterfall, where the type specimen was collected as a cultivated plant, while the yellow circle indicates Petirorano, the presumed original source of the species.
B. Saluopa Waterfall, a lower montane site at 560 m elevation, characterized by a cool and humid climate.

Prima Wahyu Kusuma Hutabarat, Zulfadli, Kurniawan Palindondaya Bandjolu, Basrul, Muhammad Rifqi Hariri, Andhika Senatama and Siti Halimah Larekeng. 2026. Rhododendron yombuwurii (Ericaceae), A New orange-flowered Species of subgenus Vireya from Central Sulawesi, Indonesia.  Taiwania. 71(2); 277-283 DOI: 10.6165/tai.2026.71.277 [2026 March 28] 

https://taiwania.ntu.edu.tw/abstract/2170  

[Botany • 2026] Rhododendron mulunense (Ericaceae) • A New Species from the Karst Mountains of Guangxi and Guizhou Provinces, China

  

Rhododendron mulunense  Y.S.Huang & X.X.Mao,

in Hou, Huang, Luo, Chen et Mao, 2026.

木论杜鹃  ||  DOI: doi.org/10.3897/phytokeys.269.175011  

 

Abstract

Rhododendron mulunense, a new species of Rhododendron (Ericaceae) within subsect. Maddenia in sect. Rhododendron and endemic to karst areas of Guangxi and Guizhou Province, SW China, is described and illustrated. The new species most closely resembles R. wumingense, particularly in scale density on the abaxial leaf surface and in flower color and shape, but can be readily distinguished by its hairless shoots and leaves, larger tubular-funneled corolla, and longer and thinner white tube flushed with pink. According to the IUCN Red List Categories and Criteria, the threatened status of the new species is assessed as “Endangered, EN C2a(i), D.” We provide detailed documentation of its morphological characteristics, geographical distribution, digitized holotype voucher, and comparative photographs, along with a diagnostic table. An identification key is provided as a primary tool to enable taxonomic discrimination of this species from its congeners.

Key words: Conservation, morphology, Rhododendron mulunense, Rhododendron wumingense, taxonomy

Rhododendron mulunense.
 A. The habitat of this new species in type localities; B. Flowering plants; C. Leaves; D–F. Flowering branchlets, inflorescences, and flowers; G, H. Dissection of corolla; I. Flower buds; J. Stamens and style; K. Styles and ovaries; L. Dissection of ovary; M. Stigmas; N. Poorly developed stamens; O. Normal stamens; P, Q. Anther abaxial and adaxial surface; R. Tube base; S. Flower bud scales; T. Dehiscent capsule.

Photographs by Yu-Song Huang.

 Rhododendron mulunense Y.S.Huang & X.X.Mao, sp. nov.

Diagnosis. Resembles Rhododendron wumingense Fang but distinguishable by the absence of indumentum on young shoots, leaf margins, and petioles (vs. sparsely setose), longer and larger leaves (4.2–7.4 × 2.3–3.8 vs. 3.5–4.5 × 1.8–2.4 cm), relatively sparser scales on abaxial leaf surfaces (1–4 vs. 1–3 × their own diameter apart), corollas that are tubular funneled (vs. broadly funneled), longer and wider (5.9–7.5 × 4.7–7 vs. 3.1–4.5 × 3.3–4.9 cm) with slender tubes (2.9–3.9 × 0.5–1.2 vs. 1.9–2.5 × 1.7–2.4 cm), outer surface of corolla tubes white flushed with pink (vs. yellowish green) and pubescent but not scaly (vs. sparsely scaly and hairless) (Figs 1, 2, 4; Table 1).

Etymology. The specific epithet of this newly described species refers to its type localities at Guangxi Mulun National Nature Reserve, part of the South China Karst landscape registered in UNESCO’s World Heritage List.

Vernacular name. Simplified Chinese: 木论杜鹃; 

Chinese pinyin: mù lùn dù juān.

Ying Hou, Yu-Song Huang, Liu-Juan Luo, Zheng-Ren Chen, Xing-Xing Mao. 2026. Rhododendron mulunense (Ericaceae), A New Species from the Karst Mountains of Guangxi and Guizhou Provinces, China. PhytoKeys. 269: 99-112. DOI: doi.org/10.3897/phytokeys.269.175011  [08-01-2026]

[Botany • 2024] Rhododendron mulyaniae & R. engelbertii (Ericaceae) • Two New Species of Vireya Rhododendron from Tambrauw, Papua, Indonesia

Rhododendron mulyaniae Mambrasar,

in Mambrasar, Elliott et Cameron, 2024. 

DOI: doi.org/10.1111/njb.04545 

  Researchgate.net/publication/384379726 

  facebook.com/NordicJBotany

Abstract

Two new species of Vireya Rhododendron, Rhododendron mulyaniae sp. nov. and R. engelbertii sp. nov. were discovered in Tambrauw, Papua, Indonesia. Rhododendron mulyaniae resembles R. angiense in that the scales under the leaf are dendroid, but differs in having elliptic to narrowly elliptic leaves, lacking hairs on petiole, having a tubular funnel shaped corolla. Rhododendron engelbertii resembles to R. carstensense in leaf shape but differs by having narrowly tapering leaf base, scales present on the petiole, and a corolla densely scaly on the outside. Detailed descriptions, illustrations and provisional conservation threat status of these newly described species are provided.

Keywords: Gunung Botak, new species, Tambrauw, Vireya Rhododendron

 

Rhododendron mulyaniae Mambrasar sp. nov.  

Rhododendron engelbertii Mambrasar sp. nov.  

Yasper M. Mambrasar, Alan C. Elliott and Kennet M. Cameron. 2024. Two New Species of Vireya Rhododendron (Ericaceae), from Tambrauw, Papua, Indonesia. Nordic Journal of Botany. DOI: doi.org/10.1111/njb.04545 [26 September 2024]  

 Researchgate.net/publication/384379726_Two_new_species_of_Vireya_Rhododendron_from_Tambrauw_Papua_Indonesia

  facebook.com/NordicJBotany/posts/1099594055503156

[Botany • 2025] Rhododendron yuanbaoshanense (Ericaceae, subgen. Hymenanthes) • A New Species from Guangxi, China

Rhododendron yuanbaoshanense  

in Y.H. Deng, Pan, Ding, Liu, Qin, Huang et M.-M. Deng, 2025. 

DOI: doi.org/10.11646/phytotaxa.682.2.6 

 

Abstract

A new species of Rhododendron (Ericaceae) in subgen. Hymenanthes, sect. Ponticum, subsect. Fortunea from Yuanbaoshan, northern Guangxi, China, namely R. yuanbaoshanense, is described and illustrated. The new species is most similar to R. yuefengense and R. orbiculare, but it differs from R. yuefengense by its broader ovate to orbicular leaf blades with a cordate-auriculate base, cylindric petioles, and longer inflorescence rachis. It is distinguished from R. orbiculare in having 8–17-flowered inflorescences with longer rachis, funnelform-campanulate to campanulate corollas that are pink to pale pinkish-purple and sparsely glandular outside, and densely white glandular style.

China, Ericaceae, Guangxi, Rhododendron subgen. Hymenanthes, taxonomy, Eudicots

Yi-Hui DENG, Bo PAN, Tao DING, Hong LIU, Xue-Lian QIN, Zi-Xiong HUANG and Min-Min DENG. 2025. Rhododendron yuanbaoshanense (Ericaceae), A New Species from Guangxi, China. Phytotaxa. 682(2); 179-184. DOI: doi.org/10.11646/phytotaxa.682.2.6 [2025-01-21] 

[Botany • 2024] Rhododendron tyaihyonii & R. kantoense • Unraveling Enigmatic Disjunctions: Population Genetic Analysis Points to Independent Origins of Rare Rhododendrons in the Rhododendron keiskei complex (Ericaceae)

 

  the Rhododendron keiskei complex. B–D, Morphological comparisons of:
B, Rhododendron keiskei Suzuki (1932) R. keiskei var. keiskei;
C, Rhododendron kantoense S.Sakag. & Y.Watan., nom. & stat. nov. R. keiskei var. hypoglaucum;
D, Rhododendron tyaihyonii S.Sakag., H.J.Choi & S.C.Kim, sp. nov. Rhododendron sp.

in Sakaguchi, H.-J. Choi, Yoichi, Takahashi, ..., H.-J. Choi et S.-C. Kim, 2024. 

 DOI: doi.org/10.1002/tax.13288 

 facebook.com: Shota Sakaguchi

 — Photos: B, Shota Sakaguchi; C, Watanabe Yoichi; D, J.-C. Yang.

 

Abstract

Unraveling species boundaries is pivotal for evolutionary biology and conservation endeavors. However, it proves challenging in instances where recent speciation is intertwined with complex demographic histories and natural selection processes. The Rhododendron keiskei complex, an evergreen rhododendron distributed in East Asia, consists of a widespread variety (R. keiskei var. keiskei) and a more restricted R. keiskei var. hypoglaucum. Intriguingly, the latter is exceptionally rare yet displays a disjunction that spans approximately 1100 km. This study aimed to elucidate the evolutionary backgrounds of the enigmatic disjunctions of R. keiskei var. hypoglaucum and to propose species delimitation within the species complex. An integrative approach, combining genomic data (MIG-seq and GBS-derived SNPs) with Scanning Electron Microscopy analysis of leaf microstructures was adopted in this study. Phylogenetic analyses revealed significant divergence among the studied rhododendrons. Genetic demographic analyses favored the population models that assumed non-monophyly of two disjunct populations of R. keiskei var. hypoglaucum indicating their independent origins. Recent gene flow between the widespread R. keiskei var. keiskei and “var. hypoglaucum” populations were limited due to geographic and habitat isolation factors, even in areas where their distributions overlap. Detailed morphological assessments detected distinctions between morphologically similar “var. hypoglaucum” populations based on leaf microstructures and flowering habits. Our study has shown that the apparent disjunctions of rare rhododendrons are more likely attributed to morphological convergence, possibly due to similar environmental selections in unrelated taxa. The finding highlights the importance of an integrative approach for resolving taxonomic challenges in plant species complexes.

Keywords: demographic modeling, disjunct distribution, East Asia, endangered species, phylogeny, species delimitation

A) Rhododendron tyaihyonii; B) R. kantoense; C) R. keiskei 

R. keiskei var. keiskei

R. keiskei var. hypoglaucum (R. kantoense nom. & stat. nov.)

Rhododendron sp. (R. tyaihyonii sp. nov.; formerly identified as var. hypoglaucum)

A, The geographic distribution of the Rhododendron keiskei complex.
B–D, Morphological comparisons of: B, R. keiskei var. keiskei; C, R. keiskei var. hypoglaucum; D, Rhododendron sp. 
E, Comparison of leaf blade morphology of three taxa, based on the voucher specimens (suppl. Table S1). Note that the leaf morphological variation of R. keiskei var. hypoglaucum and Rhododendron sp. overlap. — Photos: B, Shota Sakaguchi; C, Watanabe Yoichi; D, J.-C. Yang.

Rhododendron tyaihyonii S.Sakag., H.J.Choi & S.C.Kim, sp. nov. 

Distribution: SOUTH KOREA. Jeollanam-do, Yeosu-si, Samseon-myeon. Narrowly endemic to Daesambudo Island.

Ecology: The plants are found on the northern slope of Daesambudo Island. They inhabit coastal rocky places with the evergreen woody species of Rhaphiolepis indica var. umbellata (Thunb.) H.Ohashi, Ligustrum japonicum Thunb., Camellia japonica L, Litsea japonica (Thunb.) Juss.

Etymology: The specific epithet, “tyaihyonii”, is named in honor of Chung Tyaihyon (1883–1971), known as the father of plant taxonomy in Korea and the first curator of Sungkyunkwan University Herbarium (Ha Eun Herbarium, SKK). We have a better understanding of Korean flora thanks to his work in the early to mid-1900s.

Korean name: Seom-Jin-Dal-Rae.

Japanese name: Chosen-Hikage-Tsutsuji.

English name: Tyaihyon's rhododendron.

Rhododendron kantoense S.Sakag. & Y.Watan., nom. & stat. nov. 

≡ Rhododendron keiskei var. hypoglaucum Suto & T.Suzuki in Trans. Nat. Hist. Soc. Formosa 22: 23. 1932 

– Holotype: JAPAN. Kanto District, Tochigi (Shimotsuke), Kanuma, Mt. Ozaku, 1 May 1931, E. Kitamura ST3902 (TAI barcode TAI 119040 [image!] [fl.]; isotype: TNS barcode TNS 55292 [image!]).

Note: Rhododendron kantoense is similar to R. tyaihyonii, the differences being: the latter has petiole 4–7 mm long; stomata type anomocytic; inflorescence with 2–6 flowers.

Distribution: JAPAN. Kanto, Prefectures of Tochigi, Gunma, Saitama and Tokyo. Endemic to the chert and limestone mountain ridges of Kanto District.

Etymology: The specific epithet “kantoense” is derived from the Kanto District, where this species is distributed.

Japanese name: Urajiro-Hikage-Tsutsuji.

Korean name: Il-bon-Huin-Jin-Dal-Rae.

English name: Kanto rhododendron.

 

Shota Sakaguchi, Hee-Joo Choi, Watanabe Yoichi, Daiki Takahashi, Shun K. Hirota, Masayuki Maki, Shoki Murakami, Taichi Harada, Nobuo Kobayashi, Yuji Kurashige, Jun-Ho Song, Hyeok-Jae Choi and Seung-Chul Kim. 2024. Unraveling Enigmatic Disjunctions: Population Genetic Analysis Points to Independent Origins of Rare Rhododendrons in the Rhododendron keiskei complex (Ericaceae). TAXON. DOI: doi.org/10.1002/tax.13288

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[Botany • 2021] Rhododendron kuomeianum (Ericaceae, sect. Rhododendron) • A New Species from northeastern Yunnan (China), based on Morphological and Genomic Data

Rhododendron kuomeianum Y.H. Chang, J. Nielsen & Y.P. Ma,

in Chang, Yao, Neilsen, Liu, Zhang et Ma, 2021.   

DOI: 10.1016/j.pld.2021.04.003 

 Researchgate.net/publication/351276252

Abstract

Rhododendron kuomeianum Y.H. Chang, J. Nielsen & Y.P. Ma, a new species of Rhododendron (Ericaceae) within subsect. Maddenia in sect. Rhododendron from Yiliang County, NE Yunnan, China, is described and illustrated. The new species is similar to R. valentinianum, but it can be easily distinguished by its sparse scales on the abaxial surface of the leaf blade, fewer flowers per inflorescence and white corolla with pale red margins. There are also differences in the widths of calyx lobes, leaf blade shape and indumentum characteristics of the petiole between the new species and Rhododendron linearilobum. We confirmed that R. kuomeianum is a new species closely related to R. valentinianum and R. changii with phylogenomic studies of 10 species within this subsection based on restriction site-associated DNA sequencing (RAD-seq) data. These phylogenomic analyses also clarified additional taxonomic problems in this subsection previously raised by morphological analysis. Our findings make a strong case for using next-generation sequencing to explore phylogenetic relationships and identify new species, especially in plants groups with complicated taxonomic problems.

 

Keywords: Rhododendron, New species, RAD-seq, Phylogenetic position

 Illustrations of Rhododendron kuomeianum Y.H. Chang, J. Nielsen & Y.P. Ma sp. nov.
(A) habit; (B) corolla; (C) dissected corolla; (D) inflorescence bud; (E) flower bud; (F) stamen; (G) pistil and calyx; (H) leaf adaxial surface; (I) leaf abaxial surface; (J) distribution of scales on the adaxial surface of the leaf blade; (K) single scale on the abaxial surface of leaf blade; (L) capsule.

 Drawn by R.M. Zhang. 

 Rhododendron kuomeianum Y.H. Chang, J. Nielsen & Y.P. Ma sp. nov.
(A–B) plant and habitat; (C–D) leaf; (E) inflorescence bud; (F) corolla anatomy; (G) fruit.

Scale bar = 1 cm.

 

Rhododendron kuomeianum Y.H. Chang, J. Nielsen & Y.P. Ma sp. nov. 

 国楣杜鹃【guó méi dù juān】

Type. CHINA. Yunnan: Yiliang County Xiaocaoba Nature Reserve, ....

Diagnosis. Rhododendron kuomeianum resembles R. valentinianum in having a broadly elliptic to obovate leaf blade, dense rusty-yellow setae on the petiole, and a funnelform-campanulate corolla. It differs from R. valentinianum in having a white corolla with pale red margins (versus light to bright yellow), fewer flowers (1–2) per inflorescence (versus 2–4), and sparser distribution of scales on the abaxial surface of the leaf blade (1–2 × scales diameter apart) (versus 0.5 × scales diameter apart) (Table 1).

Etymology. The new species Rhododendron kuomeianum was named after Professor Kuo Mei Feng, a botanist and horticulturalist from the Kunming Institute of Botany, Chinese Academy of Sciences, to honor his great contribution to research on the genus Rhododendron in China. In pinyin, the Chinese name is “Guó méi dù juān”.

 Yu-Hang Chang, Gang Yao, Jens Neilsen, De-Tuan Liu, Lu Zhang and Yong-Peng Ma. 2021. Rhododendron kuomeianum (Ericaceae), A New Species from northeastern Yunnan (China), based on Morphological and Genomic Data. Plant Diversity. 43(4); 292-298. DOI: 10.1016/j.pld.2021.04.003

  Researchgate.net/publication/351276252_Rhododendron_kuomeianum_a_new_species_from_northeastern_Yunnan_China

[Botany • 2021] Rhododendron tephropeploides & R. chunii subsp. vietnamense (Ericaceae) • Two New Taxa of Rhododendron from Northwest Vietnam

Rhododendron tephropeploides  R.A.Baines & D.F.Chamb.

in Baines, Chamberlain, et al., 2021. 

DOI:  10.24823/EJB.2021.363

ABSTRACT

Two new taxa from Vietnam are described and illustrated: Rhododendron tephropeploides, in subsection Tephropepla, and R. chunii subsp. vietnamense, in subsection Tsutsusi.

Keywords: Ericaceae, Phan Xi Păng, Rhododendron chunii subsp. vietnamense, Rhododendron tephropeploides, Vietnam

Rhododendron tephropeploides  R.A.Baines & D.F.Chamb., sp. nov.
 RBGE accession no. 20150482 flowering at Logan Botanic Garden.

Photographs: R. A. Baines.

Rhododendron tephropeploides R.A.Baines & D.F.Chamb., sp. nov.

 (subsect. Tephropepla)

Similar to the allied Rhododendron tephropeplum Balf.f. & Farrer, a species from Northeast India, northern Myanmar and Southwest China, but differs in the dimorphic scales on the lower leaf surfaces; the smaller, 1-mm calyx lobes; the larger funnel-shaped, whitish to pale pink 30–35 mm corollas that are glabrous on the outer surfaces; and the glabrous stamens.  

 Ecology. Temperate montane cloud forest, in wet thin soil with high humus content and high humidity. The surrounding vegetation is characterised by Hydrangea, Illicium and Rhododendron.

Rhododendron chunii W.P.Fang subsp. vietnamense R.A.Baines & D.F.Chamb., subsp. nov.

(subsect. Tsutsusi)

Rhododendron chunii subsp. chunii differs from the new subspecies in the young stems that bear appressed bristles that apparently lack the stipitate glands of subsp. vietnamense, and in the outer surface of the corolla tube that is glandular.

Ecology. Temperate montane cloud forest, in wet thin soil with high humus content and high humidity. The surrounding vegetation is characterised by Enkianthus, Pieris and Rhododendron

R. A. Baines, D. F. Chamberlain, V. D. Nguyen and B. H. Quang. 2021.  Two New Taxa of Rhododendron (Ericaceae) from Vietnam. EDINBURGH JOURNAL OF BOTANY. 78, 363. DOI:  10.24823/EJB.2021.363

[Botany • 2020] Rhododendron pudingense (Ericaceae: Subgen. Tsutsusi) • A New Species of Rhododendron from Guizhou, China

 Rhododendron pudingense X.Y. Dai, C.H. Yang & Y.P. Ma

in Dai, Yang, Yang, et al., 2020.

 DOI: 10.3897/phytokeys.146.51342

Abstract
A new species of the Rhododendron (Ericaceae) in subgen. Tsutsusi sect. Tsutsusi from Puding county of Guizhou, China, is described and illustrated. The new species, Rhododendron pudingense X.Y. Dai, C.H. Yang & Y.P. Ma, is similar to R. myrsinifolium Ching ex Fang et M. Y. He and R. minutiflorum Hu, but it can be easily distinguished by its length and being pubescent on inner surface of corolla tube, sparse hairs below the middle of filament and the glabrous style.

Keywords: China, Ericaceae, Guizhou, Rhododendron, R. pudingense, Tsutsusi

Figure 1.  Rhododendron pudingense X.Y. Dai & C.H. Yang, sp. nov. 
A fruiting branch B flowering branch C leaf abaxial D flowers E side view of flower F stigma and ovary G stamen H capsule.

Figure 2.  Rhododendron pudingense X.Y. Dai & C.H. Yang, sp. nov. 
A habitat B one flowering plant C inflorescence D flower viewed from different angles as well as stigma and filaments E fruit branch.

Rhododendron pudingense X.Y. Dai, C.H. Yang & Y.P. Ma., sp. nov.

Etymology: The specific epithet is named after the type locality Puding County, in which this plant was first discovered.

Vernacular name: Chinese mandarin: pǔ dìng dù juān (普定杜鹃)


Distribution and habitat: So far, this species is only known from the type locality (Pudding County) and from the Wangmo County, Guizhou Province, southwest China. At these locations Rhododendron pudingense grows in evergreen and deciduous broad leaved mixed open forests within the rock cracks of limestone hills, at an elevation of 1300 m to 1400 m.

 Xiao-Yong Dai, Cheng-Hua Yang, Bing Yang, Pu Chen and Yong-Peng Ma. 2020. A New Species of Rhododendron (Ericaceae) from Guizhou, China. PhytoKeys. 146: 53-59. DOI: 10.3897/phytokeys.146.51342

     

[Botany • 2019] Rhododendron widjajae (Ericaceae: Section Schistanthe) • A New Species from Sulawesi, Indonesia

Rhododendron widjajae Argent & Mambrasar

in Argent & Mambrasar, 2019.

  DOI: 10.14203/reinwardtia.v18i1.3700   

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A new species of Rhododendron section Schistanthe (= subgenus Vireya) is described, Rhododendron widjajae Argent & Mambrasar. It is compared with the two most similar species and the differences demonstrated.

Key words: Ericaceae, Indonesia, Mt. Mekongga, new species, Rhododendron, Sulawesi.

 Rhododendron widjajae Argent & Mambrasar, spec. nov.

Photograph of the living plant from type location.

 Photo: Elizabeth A. Widjaja.

Rhododendron widjajae Argent & Mambrasar, spec. nov.

Diagnosis. Similar to Rhododendron pseudobuxifolium Sleumer in its size of flower. It differs in having twigs which are without the short hairs of that species; in having pedicels without simple hairs and the corolla is sparsely scaley outside not glabrous and glabrous inside, not shortly hairy. Superficially similar to R. celebicum (Blume) DC. but smaller and significantly differing from that species by the hairy filaments and ovary.

Habitat and ecology. Mt. Mekongga is a volcanic peak rising to 2,779 m in the north-west part of South East Sulawesi. This new species was collected in the sub-alpine area at 2,658 m asl. which is close to the summit (2,779 m). This area is described as: jagged limestone karst and the Rhododendron was probably an epiphyte. The associated species have not been recorded but will no doubt have been semi-open dwarf shrubs.

Etymology. Named in honour of Prof. Elizabeth A. Widjaja, former senior researcher at the Herbarium Bogoriense and joint collector of this species for her contribution to Indonesian botany.

 George Argent and Yasper Michael Mambrasar. 2019. Rhododendron widjajae (Ericaceae, Section Schistanthe) A New Species from Sulawesi.  Reinwardtia. 18(1); 27‒30. DOI: 10.14203/reinwardtia.v18i1.3700    

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