Perianth Tube Research Articles

Aspidistra tripartita (Asparagaceae, Convallarioideae), a new species from Vietnam

Aspidistra tripartita, a new species of Asparagaceae, is described and illustrated. The species was discovered in 2019 in Son La Province, northern Vietnam. Aspidistra tripartita belongs to a group of species characterized by campanulate to cupulate perianth tube and deeply lobed stigma. The new species is readily distinguishable from the other species of this group by thick rhizome (more than 10.5 mm in diameter), long and narrow ensiform leaf blades (28–71.5 cm long and 2.6–3.1 cm wide), and stamens with supraconnectives.

Disruption of pollination by herbivores is rescued by nectar yeasts

Abstract Attracting pollinators to achieve successful reproduction is a key challenge for wild plants that may be disturbed by complex multispecies interactions in nature. Pairwise plant–pollinator interactions have traditionally been studied for decades, while ignoring other ecological players may obscure a comprehensive understanding on how plants recruit partners or combat enemies in the pollination process. Hence, integrated studies considering the inherent complexity of ecological interactions are needed, which may open up new perspectives for deciphering intricate systems and predicting ecological consequences. We examined the presence of nectar yeasts using a combination of high‐throughput sequencing, cultivation and microscopy and quantified floral herbivory by evaluating the incidence of flowers with visible holes in 13 natural populations of Iris bulleyana in the Hengduan Mountains of southwest China during 2017–2022. We combined yeast inoculation and herbivore manipulation treatments to illustrate the isolated and combined impacts of two contrasting nectarivorous organisms, the ascomycetous yeast Metschnikowia reukaufii and adult sawflies, on pollinator visitation and plant reproductive success in two populations. In the lab, we first employed gas chromatography–mass spectrometry to profile the volatile metabolites of yeast‐inoculated nectar relative to control, followed by a behavioural bioassay to test the preference of honeybees for these microbial volatiles. Yeasts commonly inhabited floral nectar and insect herbivores frequently bit holes in the perianth tube to consume nectar and nectaries. Nectar yeasts indirectly facilitated plant reproduction through increased pollinator visits, probably because of microbial metabolism as honeybees preferred nectar volatiles produced by yeasts in behavioural bioassays. Insect herbivores increased total floral visits but reduced legitimate visits by inducing legitimate‐to‐robbing behavioural changes of honeybees, thus leading to lower seed production. The detrimental effect of herbivory was mitigated by the presence of yeasts, which diminished the relative proportion of robbing visits and thereby ‘rescued’ flowers from reproductive failure. Synthesis: Overall, we found contrasting effects of non‐pollinator species, including both micro‐ and macro‐organisms, on plant–pollinator interactions in a biodiversity hotspot, where pollination deficit may be a ubiquitous phenomenon. Our findings suggest that both microbial and herbivory effects are likely to be important in explaining the exact causes of pollen limitation in species‐rich areas, highlighting the biological context dependence of species interactions in natural ecosystems.

Comparative assessment of morphological, cytological, and reproductive characteristics of the spontaneous mixoploid ‘MM 2×/4×’ and its diploid counterpart ‘Miss Manilla’ in Bougainvillea (Bougainvillea × buttiana Honlttum & Standl.)

Polyploidization-triggered chromosome multiplication typically leads to improved agronomic and ornamental characteristics in plants. However, mixoploidy may sometimes occur in spontaneous and artificially induced polyploidization events, and the deficiency of basic information about mixoploidy limits its application in breeding. In this study, the ploidy stability of spontaneous mixoploidy Bougainvillea × buttiana ‘Miss Manila’ (‘MM 2×/4×’) was validated through chromosome counting and flow cytometry analysis. Compared with its diploid counterpart ‘MM 2×’, ‘MM 2×/4×’ exhibited significantly larger size in the morphological characters related to leaf, bract, thorn, and perianth tube. The average length, width, and density of stomata in ‘MM 2×/4×’ were also significantly larger than in ‘MM 2×’, while the stomatal density of mesophyll cells decreased. The anthers of ‘MM 2×/4×’produced both 1n and 2n pollen grains, which in vitro germinated reached 8.92 %, significantly higher than ‘MM 2×’ (0.36 %). The seed setting rate of the crossing combinations ‘MM 2×/4×’ × ‘Chitra’, ‘Chitra’ × ‘MM 2×/4×’ and ‘MM 2×/4×’ × ‘Bixi’ were 65.47 %, 32.36 %, and 53.17 %, respectively, and the ploidy levels among different offspring individuals of the same genetic population are relatively consistent. While ‘MM 2×’ could not be hybrid with either the tetraploid ‘Chitra’ or diploid ‘Bixi’. Therefore, the mixoploid ‘MM 2×/4×’ partially restored the fertility of gametes and might be employed for both ploidy breeding directly and creating hybrid segregation populations in bougainvillea for trait genetic dissection.

Rohdea gymnogyna (Asparagaceae), a new species from southern Gansu, China

Rohdea gymnogyna, a new species from southern Gansu Provinces in northwestern China, is described and illustrated. It is apparently most closely related to R. rotiformis described from Sichuan, southwestern China. These two species share a smooth annular ledge appendage at the throat of the perianth tube. It is, however, readily distinguishable mainly by the lanceolate perianth lobes which strongly curved into a "W" shape in longitudinal section, the very short and bowl-shaped perianth tube, the ovary extends beyond the perianth tube. The taxonomic relationships of the new species to R. urotepala and R. lichuanensis also with an annular ledge appendage were also briefly discussed.

Moraea saxatilis (Iridaceae: Iridoideae), a new montane species from the Groot Winterhoek Wilderness Area of the Cape Floristic Region, South Africa

The new species Moraea saxatilis Goldblatt & J.C.Manning (Iridaceae: Iridoideae) is a narrow endemic of the Kliphuisvlakte above Porterville in Western Cape, South Africa. First recorded in September 2019, M. saxatilis is restricted to shallow, seasonally waterlogged soils on sandstone sheets. This diminutive species has unusual terete leaves with a median dorsal translucent line, and distinctive pale lilac flowers irregularly speckled or streaked with dark blue towards the centre, with the filaments ±free or connate only in the basal third. The acaulescent habit and ±campanulate flowers with subequal tepals connate below in a solid perianth tube and reduced style crests place the species in subg. Galaxia (Thunb.) Goldblatt & J.C.Manning. Within the subgenus, the fringed style branches of M. saxatilis place it in ser. Galaxia, which currently includes nine species, all with white or yellow flowers. Among these, only M. luteoalba has ±free filaments but it differs considerably from M. saxatilis in having plane, ovate to elliptic leaves and larger yellow flowers sometimes creamy white distally.

Rohdea brachyanthera (Asparagaceae), a new species from Guangdong, southern China

Rohdea brachyanthera, a new species from Nanling National Reserve of northern Guangdong, China, is described and illustrated. It is most similar to R. fargesii var. tsinlingensis in the perianth tube bearing an appendage at apex and the stamens are attached to it, but differs in the smooth inner surface of the perianth and stamens; the presence of six rib-like protrusions on the internal surface of the perianth tube; a ring-shaped, succulent appendage that is outwardly swollen and smooth on the surface and dilated triangular filaments that are united with the appendages at the base. Information on the habitat and phenology as well as notes on the taxonomic relationships with other congeners is also provided.

Mechanistic understanding of perianth traits hindering pollination in Aristolochia contorta Bunge.

Insects are vital pollinators for angiosperms, playing a crucial role in their reproductive success and fruit production. Aristolochia contorta is a perennial herbaceous vine that occurs in fragmented populations across East Asia. One notable feature of this plant is its trap flower, which employs a unique mechanism to attract, trap, retain, and release insects, ensuring effective pollination. The presence of this trap flower significantly influences the pollination system of A. contorta. Field surveys and pollination experiments were conducted to understand the processes and effectiveness of its pollination mechanism. It was allogamous and was pollinated by the species from Ceratopogonidae. During the insect attraction stage, 11.57% of the flowers contained insects, primarily Ceratopogonidae spp. Most Ceratopogonidae spp. concentrated in few flowers, indicating that although overall attraction might be modest, specific flowers acted as significant focal points for gathering. Trichomes effectively trapped Ceratopogonidae spp. inside flower tubes. In the retention stage, 26.16% of Ceratopogonidae spp. were loaded with pollen grains, but only 7.91% of those exited the flowers in the release stage. The sticky texture of the perianth's internal cavity posed challenges during this release, leading to adhesion and clogging of the narrow perianth tube. Consequently, a significant portion of Ceratopogonidae spp. became trapped on the perianth wall and perished. This highlights that despite the significant energy and resources invested in flower development, the perianth contributes to the low pollination effectiveness. This study revealed additive factors with negative effects on pollination, including the densely clustered distribution of its pollinators within only a few flowers, insufficient pollen loading onto pollinators, hindered release of entrapped pollinators due to the perianth adhesive surface, and a high rate of defective pollen grains in A. contorta. These factors account for the observed phenomenon of low fruit set (7.7%) and contribute to the diminished rate of sexual reproduction in A. contorta populations. This might lead the species to heavily rely on asexual reproduction, which could potentially lead to gene erosion within populations. The implications of these findings extend to the ecological and conservation aspects, emphasizing the need to understand and conserve the unique pollination system of A. contorta.

Clermontiahanaulaensis (Campanulaceae, Lobelioideae), a new, critically endangered species from Maui, Hawaiian Islands.

Clermontiahanaulaensis H.Oppenheimer, Lorence & W.L.Wagner, sp. nov., a newly discovered, narrowly distributed endemic species, is herein described based on its morphological characteristics and illustrated with field photos and a line drawing. It is currently known only from the slopes of Hana'ula, in Pōhākea Gulch, Mauna Kahālāwai, west Maui, Hawaiian Islands. It differs from all other species of Clermontia Gaudich. by the combination of its (2)3-4(-5) flowered inflorescence, violet colored perianth often suffused with creamy white streaks or sometimes creamy white with violet-purple irregular veins, (30)35-45(-50) mm long, perianth tube 15-25(-27) mm long, 9-10 mm wide, the lobes 20-26 mm long, (2-)3-3.5 mm wide, with petaloid calyx lobes 1/2-4/5 as long as the petals. A key to the Clermontia species and subspecies occurring on Maui is provided. Its habitat is described. Its conservation status is proposed as critically endangered (CR), and conservation efforts are discussed.

Aristolochia laotica (subgen. Siphisia), a new species from Northeastern Laos

Aristolochia laotica, a new species from Northeastern Laos, is described and illustrated here. The horseshoe-shaped perianth tube, the 3-lobed limb, and the 3-lobed gynostemium support its placement into Aristolochia subgenus Siphisia. Of the species with cylindric or saccate-shaped limb, the new species resembles A. vuquangensis. However, it differs from the latter by having an oblanceolate to narrowly elliptic leaf lamina with a truncate to shallowly cordate base, pinnate veins, sparsely brown hirsute to glabrescent perianth, uniformly purple inner surface of utricle, indistinct, straight, strongly inflated limb lobes, and pubescent and warty inner surface of the limb lobes. Detailed description, color illustrations, and remarks on ecology, conservation status are also provided, along with a key to species reported in Laos and comparison with its similar species.

Gastrodiabawanglingensis (Orchidaceae, Epidendroideae), a new species from Hainan Island, China.

Gastrodiabawanglingensis, a new species of Orchidaceae from Hainan Island, China, is described and illustrated. It is morphologically similar to G.theana, G.albidoides and G.albida with dwarf habits, scarcely opening flowers, elongated fruit stems, curved and fleshy perianth tubes and similar columns and lips, but can be easily distinguished from them by having a pair of lateral wings bent outwards at the apex of the column and lateral wings with acuminate tips lower than the anther. According to the IUCN Red List Categories and Criteria, the new species is assessed as Endangered (EN). The plastome of G.bawanglingensis is greatly reduced and reconfigured with approximately 30876 bp in size and 25.36% in GC content. Morphological characteristics and molecular phylogenetic results based on chloroplast gene sequences support the recognition of G.bawanglingensis as a new species within Gastrodia.

The Study on Sea Buckthorn (Genus Hippophae L.) Fruit Reveals Cell Division and Cell Expansion to Promote Morphogenesis.

Due to its unique flavor and high antioxidant content, the sea buckthorn (genus Hippophae L.) fruit is increasingly favored by consumers. Developing from the perianth tube, the sea buckthorn fruit varies greatly among species in both size and shape. However, the cellular regulation mechanism of sea buckthorn fruit morphogenesis remains unclear. This study presents the growth and development patterns, morphological changes, and cytological observations of the fruits of three Hippophae species (H. rhamnoides ssp. sinensis, H. neurocarpa, and H. goniocarpa). The fruits were monitored every 10-30 days after anthesis (DAA) for six periods in their natural population on the eastern margin of the Qinghai-Tibet Plateau in China. The results showed that the fruits of H. rhamnoides ssp. sinensis and H. goniocarpa grew in a sigmoid mode, while H. neurocarpa grew in an exponential mode under the complex regulation of cell division and cell expansion. In addition, cellular observations showed that the mesocarp cells of H. rhamnoides ssp. sinensis and H. goniocarpa were larger in the area with prolonged cell expansion activity, while H. neurocarpa had a higher cell division rate. Elongation and proliferation of the mesocarp cells were found to be essential factors affecting the formation of fruit morphology. Finally, we established a preliminary cellular scenario for fruit morphogenesis in the three species of sea buckthorn. Fruit development could be divided into a cell division phase and a cell expansion phase with an overlap between 10 and 30 DAA. In particular, the two phases in H. neurocarpa showed an additional overlap between 40 and 80 DAA. The description of the sea buckthorn fruit's transformation and its temporal order may provide a theoretical basis to explore the growth mechanism of fruits and regulate their size through certain cultivation techniques.

Occultia (Scilloideae, Asparagaceae), a new genus from Malawi and Mozambique

A new genus Occultia (Scilloideae, Asparagaceaae), is described from Malawi and Mozambique. One of the species on which this genus is based, was originally described as Hyacinthus. The genus is clearly separated from Ledebouria and closely related genera in characters of the flowers and the fruits. In Occultia tepals are united for 1/3 to ½ their length, the filaments are very short and inserted at the top of the perianth tube. In the fruiting stage, the tepals of the new genus become membranous and detached from their basis, but may form a cap on the developing capsule. In Ledebouria the tepals are free or united just at the base, the filaments are of a certain length and inserted at the base of the tepals. If persisting at fruiting stage the tepals are attached to the base of the capsule, and may become fleshy with time. The new genus comprises two species O. hyacinthoides and O. fragrans.

Flame-lilies and Christmas Bells: The genera Gloriosa L. and Sandersonia Hook. (Colchicaceae: Colchiceae) in Southern Africa

The genera Gloriosa L. and Sandersonia Hook. (Colchicaceae: Colchiceae) are revised for southern Africa, with full nomenclature, descriptions, distribution data and updated conservation assessments. All species are illustrated in colour. Both genera have a similar habit, with mostly cirrhose foliage and yellow (rarely greenish) to orange flowers nodding on slender extra-axillary pedicels, with a well-developed style longer than the branches. Despite their similar morphology, existing phylogenetic analyses indicate that they are not immediately related. Three species of Gloriosa are recognised from the region, distinguished by the shape and size of their flowers, and the orientation and relative length of the style. Gloriosa superba L., which is widespread through Africa and southeast Asia, is recognised by its relatively large flowers with recurved or reflexed tepals that are narrowed and ± clawed at the base, and a sharply flexed style. Capsule dehiscence is septicidal. Typical plants have a bicoloured red and yellow perianth but populations from the north-eastern parts of the subcontinent and also elsewhere in tropical Africa are predominantly plain yellow. The overlooked G. sect. Gloriola Chiov. is lectotypified against G. aurea Chiov., currently treated as a synonym of G. superba. A full nomenclator and synonymy of all names included in G. superba is provided for the first time, including the nomenclatural status of the names and their types. The two remaining species in the region share similar cup-shaped flowers with suberect, lanceolate tepals and erect style. The locally endemic G. rigidifolia (Bredell) J.C.Manning & Vinn. from the Waterberg in Limpopo, South Africa, has been confused with G. modesta (Hook.) J.C.Manning & Vinn. from eastern South Africa, Eswatini and Mozambique but it differs consistently from that species in its erect, mostly more floriferous habit and in its slightly smaller, greenish (vs mostly yellow or orange) flowers with slightly longer perianth tube and much longer style, and evidently also in its septicidal (vs loculicidal) capsule dehiscence. The two taxa constitute a species pair that differs from florally similar species from tropical Africa by the mostly whorled foliage and unusual nectaries with an auricle-like distal lobe on the lateral ridges. The monotypic genus Sandersonia is distinguished by its 3(5)-veined leaves, urceolate or lantern-shaped flowers with small, pouched or shortly spurred nectary, and verrucose seeds. The single species S. aurantiaca Hook. is endemic to temperate grasslands in South Africa and adjacent Eswatini.

Geissorhiza seracina (Iridaceae: Crocoideae), a new high-altitude species from the Langeberg in southwestern Western Cape, South Africa, with notes on G. outeniquensis

• Geissorhiza seracina is described. • It is a local endemic of the eastern Langeberg. • It is illustrated by colour photographs. • It is distinguished from G. altimontana by a longer perianth tube and filaments. The new species Geissorhiza seracina Goldblatt & J.C.Manning (Iridaceae: Crocoideae) is known from a single locality on the central Langeberg Mountains in Western Cape, South Africa. Discovered in December 2021, G. seracina is restricted to high altitude seepages in peaty soils. The soft corm tunics and moderately large, deep pink flowers suggest that it is allied to another Langeberg endemic, G. altimontana Goldblatt & J.C.Manning of subg. Weihea sect. Weihea , but it differs from that species in lacking fibrous leaf bases, in its mostly fewer leaves, and in its flowers, which have a longer perianth tube 18–23 mm long, with longer filaments, 11–12 mm long, inserted well below the mouth of the tube. It is illustrated by colour photographs. In addition, re-examination of collections of the poorly collected G. outeniquensis Goldblatt necessitates that the recorded length of the perianth tube for that species be significantly extended. Originally recorded as 10–13 mm long, the perianth tube in G. outeniquensis is now determined to be (10–)13–20 mm long.

Thismia cordata (Thismiaceae), a new fairy lantern species from the Brazilian Atlantic Forest

A new species of Thismia (Thismiaceae) from the Brazilian Atlantic Forest is described and illustrated. Thismia cordata belongs to T. subg. Ophiomeris sect. Ophiomeris, and is mainly characterized by its flowers zygomorphic with gibbous perianth tube which is densely pilose on the inner surface, annulus surrounded by a prominent star-shaped ornamentation of 6-lobes with apex acute, densely pilose, outer perianth lobes ovate with base cordate, stamens with connective falcate, ovary glabrous, and stigma sharply trilobed, densely pilose. Detailed description, illustrations, notes on distribution, and preliminary conservation assessment are provided below.

A broadly sampled 3-loci plastid phylogeny of Atraphaxis (Polygoneae, Polygonoideae, Polygonaceae) reveals new taxa: III. A. kuvaevii and сryptic species in A. pungens from Southern Siberia and Northern Mongolia

Maximum Likelihood (ML) and Bayesian analyses (BI) applied for combined plastid matrix (cpDNA trnL(UAA) intron, trnL–trnF IGS, and rpl32–trnL(UAG) IGS regions) of 124 accessions of 36 species of the genus Atraphaxis have shown new species from southern Siberia. The analysis of 112 accessions of 36 species of nrDNA ITS1–5.8S–ITS2 regions showed less clear topology. A new species A. kuvaevii endemic for Yenisey Valley in Tuva was revealed with molecular and morphological data. The plants attributed previously to A. pungens split into three cryptic species with different plastid regions. A. pungens grows in the south of Krasnoyarskii Krai, Khakassia, Tuva and Mongolia. A. ledebourii is distributed in Altai Mts, Tuva and Mongolia. It combines a functional ITS ribotype and a psedogenized ribotype, what agrees with high chromosome numbers. The third pseudogenized ribotype shared with A. ariana was found in a single sample from SE Tuva. A. ×uyukensis is a species of hybrid origin from the Uyuk ridge with the ITS ribotype of A. pungens, which probably captured cpDNA of unknown species related to A. selengensis and A. davurica by maternal lineage. Despite the differences in plastid regions, these cryptic species have no clear morphoplogical distinctions. The hybrid A. pungens × A. ledebourii from Tuva and the hybrid A. ledebourii × A. pungens from Hangay Mts in Mongolia do not differ from the parents. The eastern race of A. frutescens s.l. sub A. decipiens from Tuva and Altai Republics differs from the western race of A. frutescens with a single nucleotide substitution in cpDNA trnL–trnF IGS, a distinct ITS ribotype, a short perianth tube equal to outer tepals, herbaceous tubular ochreolas and linear-lanceolate leaf blades. The hybrids A. pungens × A. decipiens and A. decipiens × A. pungens were detected in three locations in Tuva. Cryptic hybrids A. ledebourii × A. decipiens, A. ledebourii × A. frutescens, and A. decipiens × A. ledebourii were detected in Altai and Tuva Republics. Two hybrids A. decipiens × A. ledebourii have shown the capture of cpDNA of A. decipiens. Atraphaxis laetevirens is limited by the territory of Kazakhstan, Altai Republic and Dzungaria and does not grow in Tuva and Khakassia.

Lycorisinsularis (Amaryllidaceae), a new species from eastern China revealed by morphological and molecular evidence.

Lycorisinsularis S.Y.Zhang & J.W.Shao, a new fertile diploid species from coastal provinces in eastern China is described. This new species is most similar to L.sprengeri in morphology and has been misidentified as the latter for a long time. However, it can be distinguished from the latter by the relatively longer perianth tube (1.5‒2.5 cm vs. less than 1.3 cm), a characteristic that was overlooked before. Phylogenetic analysis, based on complete plastid genome, showed that L.insularis is not genetically related to L.sprengeri in the genus. The former was a sister group of L.sanguinea, while the latter was closely related to L.longituba and L.chinensis and they were respectively located on different clades that were separated at the base of the phylogenetic tree. The chromosome number of L.insularis is 2n = 22. At present, as the new species is relatively widely distributed and the wild population can normally reproduce by seeds, we evaluate it as LC (Least Concern) according to criteria of the IUCN Red List.

Thismia petasiformis (Thismiaceae), a new fairy lantern species from the Brazilian Amazon Forest

Thismia petasiformis is described and illustrated as a new achlorophyllous mycoheterotrophic species discovered in the Brazilian Amazon Forest. The species belongs to Thismia subg. Ophiomeris sect. Pyramidalis by the presence of horizontal cylindrical roots, terete stem with scattered leaves, pyramidal stigma, and stamens flattened with connective not dilated, interstaminal lobes absent and ovary with parietal placentation from the base to the top of the ovary. Thismia petasiformis differs from T. fungiformis by the perianth tube apparently trigonous with slightly curved sides, annulus inconspicuous, and inner perianth lobes forming a single hat-shaped mitre. We present a taxonomic treatment for T. petasiformis, with a detailed description, illustrations and a preliminary assessment of its conservation status following IUCN categories and criteria.

An integrated approach for the characterization of wild Crocus species adopting phenotypical and phytochemical traits

Crocus is a taxonomically complex genus, characterized by high intra- and inter-specific variability. Five wild Crocus taxa - Crocus biflorus, C. longiflorus, C. neapolitanus, C. siculus and C. thomasii from three different areas of Southern Italy (Calabria, Basilicata and Sicily) have been investigated. We considered both flower morphological traits (inner and outer perigone segments, style branches and anthers) and the chemical profile of specialised metabolites (apocarotenoids: crocins; flavonoids: flavonols) in style branches, which were determined by high-performance liquid chromatography, coupled with a diode array detector and mass spectrometry (HPLC-UV-DAD-ESI-MS). Saffron (C. sativus) was also included as the ‘control’ species. The length of perigone tube, outer and inner tepals, anthers and style branches gave the highest contribution to the discrimination of different taxa. Concerning the specialised metabolite profiles, 20 flavonols and 24 crocins have been identified and quantified in the Crocus extracts and used to discriminate among samples, confirming that Crocus taxa can be considered as an important natural source of these substances. The chemical profiles of the different populations showed some distinctive qualitative and quantitative patterns that contributed to a certain degree of discrimination among species, in fact, flavonoids content range is comprised between 2.7 and 145.9 mg/g, whereas crocins range between 19.8 and 604.0 mg/g. It is thus hypothesized that the combination of morphological and phytochemical screenings may be an effective methodology to characterize wild Crocus genotypes from Southern Italy, also in comparison to C. sativus (saffron).

Tupistra thangii (Asparagaceae), a new species from southern Vietnam

Tupistra thangii, a new species from Lam Dong Province, southern Vietnam, is described and illustrated. It is most similar to T. clarkei from eastern Nepal and northeastern India, but differs mainly in its broader leaves, upright or ascending spike, smaller flowers, laterally strongly revolute perianth lobes, stamens adnate to the subbasal portion of the perianth lobes, and whitish stigma. It also shares some key traits (e.g. internally white-striped, dark purple perianth tube) with T. natmataungensis from western Myanmar. Notes on the phenology, habitat, distribution and taxonomic relationships to several similar species are also provided.