Sepals Research Articles

Wikstroemiafragrans (Thymelaeaceae, Daphneae), a new species from Mount Danxia, China based on morphological and molecular evidence.

A new species, Wikstroemiafragrans (Thymelaeaceae, Daphneae), from Danxiashan National Park, Shaoguan, Guangdong of China is described and illustrated. It is similar to the sympatric W.trichotoma, but can be differentiated easily from the latter by its shorter racemose inflorescences, yellowish green calyx tube, and smaller leaves. It also resembles the allopatric W.fargesii, but differs from it by its strigose-pubescent ovary and disk scale that is 2- or 3-dentate apically. Phylogenetic analysis using the nuclear DNA internal transcribed spacer (ITS) region revealed that W.fragrans falls within the Wikstroemia clade; based on current sampling, W.fragrans is closely-related to W.capitata. It is also the first species of Wikstroemia known to be endemic to the Danxia landform and is classified provisionally as Critically Endangered according to the IUCN Red List Categories and Criteria.

 Polygonatumpraecox (Asparagaceae), a new species from mid-eastern China revealed by morphological and molecular evidence.

A new species, Polygonatumpraecox Y.F.Hu & J.W.Shao (Asparagaceae), is described and illustrated. This species is similar to P.cyrtonema, P.odoratum and P.caulialatum, but can be distinguished from P.cyrtonema by its racemose inflorescence, cylindrical hairless filaments and apex without a retrorse spur; from P.odoratum by its stout moniliform rhizome, straight stem and longer (1.7-2.2 cm long) floral tube; and from P.caulialatum by its upper part straight stem, yellowish-green corolla, lobes excurved and earlier flowering. The complete chloroplast genome of this new species is 155,115-155,256 bp in length. Phylogenetic analysis revealed that P.praecox is not genetically related to the above three morphological similar species, but is closely related to the two European species (P.multiforum and P.latifolium). This species is relatively common in mid-eastern China and has previously been confused with P.cyrtonema. As its wild resources have decreased in recent years due to over-exploitation for medicinal or edible purposes, we classify it as Near Threatened (NT) according to the IUCN Red List Criteria.

Thismialimkokthayi (Thismiaceae): A new mycoheterotrophic species from Genting Highlands in Pahang, Malaysia.

Thismialimkokthayi, a distinct mitriform species of the mycoheterotrophic genus Thismia, is described and illustrated. It was found at a locality in the upland areas of Genting Highlands, Pahang, Malaysia. This new species is morphologically similar to members of Thismiasect.Geomitra, but differs in several characteristics, including the colour of the floral tube, the inner surface of the floral tube with longitudinal ribs and absent transverse bars, a stamen apex with a central lobe (prolongation of the rib) and two lateral lobes (the tips of each are recurved) and a black-purplish stigma. Thismialimkokthayi is provisionally classified as Critically Endangered according to the IUCN Red List Categories and Criteria.

The Rudgea hostmanniana complex (Rubiaceae) in the Guiana Shield region

A taxonomic revision of the Rudgea hostmanniana complex in the Guiana shield region is presented. This group includes species with sheathing stipules bearing dorsal appendages, thick glabrous leaves lacking domatia, inflorescences thyrsoid to glomerulate but not regularly dichotomous, a calyx tube absent or very short, a corolla tube 2–7(–13) mm long, and fruits usually brownish when immature and turning red or orange at maturity. Eight species are recognized, among which Rudgea billietiae, endemic to Kaw Mountain in French Guiana, is newly described and illustrated; it is assessed as Endangered according to IUCN criteria. The other species are R. bolivarensis, R. cornigera, R. coussareoides, R. hostmanniana, R. maypurensis, R. pungens, and R. tanaosepala. A key to the species is presented, as well as a table summarising their diagnostic characters.

Paraphlomisjinggangshanensis (Lamiaceae), a new species from Jiangxi, China.

Paraphlomisjinggangshanensis (Lamiaceae), a new species from Jiangxi Province, China, is described and illustrated. The new species is morphologically similar to P.intermedia, but can be easily distinguished from the latter by its cordate leaf base (vs. cuneate, decurrent), stem and calyx tube with glandular hairs (vs. short pubescent), and glabrous anthers (vs. ciliate anthers). A phylogenetic analysis, based on ITS regions, suggests that P.jinggangshanensis represents a separate branch in Paraphlomis and is closely related to Clade II. It is currently known only from Jinggangshan National Natural Reserve. Because of its limited distribution and small population size, the species was assessed as Near Threatened (NT) according to the IUCN Red List Categories and Criteria.

<i>Gentiana capitata</i> Subsp. <i>hemkundiana</i> (Gentianaceae) - A New Subspecies from Hemkund, Uttarakhand, India

Gentiana capitata Buch.-Ham. ex D.Don subsp. hemkundiana M.Shabir & A.N. Shukla collected from Hemkund in Garhwal Himalaya of Uttarakhand, India is described and illustrated here. The subspecies is morphologically characterized by small stout herb, stem sub-sessile; margin of leaves broadly membranous, flowers few, not dense or clustered, calyx tube herbaceous (not membranous), lobes linear-lanceolate or narrowly oblong; stamens inserted near the middle of corolla tube; seeds membranous with rough surface or slightly reticulate. The new taxon is compared morphologically with sympatric taxa G. capitata subsp. capitata and G. capitata subsp. harwanensis (G.Singh) Halda. In addition, a diagnostic key to the close infra-specific taxa of G. capitata is also provided.

Landslide-tunnel interaction mechanism and numerical simulation during tunnel construction: a case from expressway in Northwest Yunnan Province, China

The excavation of the tunnel on the expressway in northwest Yunnan province induced landslide and a series problem such as ground surface cracks of the slope, sliding of the slope, and cracks in the tunnel lining. This research aims to reveal the interaction relationship between the tunnel and the landslide from the prospective of field monitoring and numerical simulation. Firstly, the engineering geological conditions of the slope where the tunnel was located were obtained by field investigation. The “landslide traction segment-tunnel longitudinal tensile failure” mode was put forward based on the spatial relationship between the tunnel and the landslide. Secondly, field monitoring methods were adopted to monitor the surface displacement of the slope, the deep-seated displacement of the landslide, and the propagation of cracks in the tunnel lining. Finally, three-dimensional numerical models were established to investigate the stability of the slope and the tunnel under natural conditions, tunnel excavation conditions, and rainfall conditions. The field investigation results, field monitoring results, and numerical simulation results illustrated that: (1) The tunnel traversed the traction segment of the landslide body in parallel, and tensile failure or shear dislocation failure would occur at different stages of the interaction between the tunnel and the landslide. (2) Two sliding layers were discovered in the landslide, the shallow creep sliding layer and the deep creep sliding layer, which corresponded to the tensile failure and shear dislocation failure modes proposed in the “landslide traction segment-tunnel longitudinal tensile failure” mode, respectively. (3) The slope was in an unstable state under natural conditions. The tunnel excavation disrupted the initial stress equilibrium of the slope, resulting in stress release of the surrounding rock mass. Both excavation and rainfall would exacerbate the deformation of the landslide and the tunnel. Eventually, control measures based on the control grouting technology of the steel floral tubes were suggested to counter with landslide-tunnel deformation problems.

Direct evidence supporting Darwin's hypothesis of cross-pollination promoted by sex organ reciprocity.

Summary The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar‐polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity).We used paternity analyses in experimental populations of a stylar‐dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions.The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection.We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.

Floral phenology of an Andean bellflower and pollination by buff-tailed sicklebill hummingbird.

The Andean bellflowers comprise an explosive radiation correlated with shifts to specialized pollination. One diverse clade has evolved with extremely curved floral tubes and is predicted to be pollinated exclusively by one of two parapatric species of sicklebill hummingbirds (Eutoxeres). In this study, we focused on the floral biology of Centropogon granulosus, a bellflower thought to be specialized for pollination by Eutoxeres condamini, in a montane cloud forest site in southeastern Peru. Using camera traps and a pollination exclusion experiment, we documented E. condamini as the sole pollinator of C. granulosus. Visitation by E. condamini was necessary for fruit development. Flowering rates were unequivocally linear and conformed to the “steady‐state” phenological type. Over the course of >1800 h of monitoring, we recorded 12 E. condamini visits totaling 42 s, indicating traplining behavior. As predicted by its curved flowers, C. granulosus is exclusively pollinated by buff‐tailed sicklebill within our study area. We present evidence for the congruence of phenology and visitation as a driver of specialization in this highly diverse clade of Andean bellflowers.

흡수식 냉동기용 유하액막식 증발기의 전열관 형상이 열전달 성능에 미치는 영향

To understand the mechanism and obtain data that can be used for design, an experimental apparatus was constructed to investigate the heat transfer characteristics of a falling film evaporator for an absorption chiller. Evaporators with plain tubes or three enhanced tubes were prepared. The enhanced tubes were designed to improve surface wetting rate with surface protrusions or a floral pattern shape. The performance change of the evaporator was investigated according to the flow rate of chilled water, the inlet temperature of the chilled water, the liquid film Reynolds number, and the evaporation temperature. In the case of using the enhanced tube, the average heat transfer rate was approximately 16.3% higher than that of the plain tube, and the difference in heat transfer rate between the enhanced tubes was as small as approximately 6%. The Nusselt number of end-cross, end-dimple, and end-dimple floral tubes was higher by 13.1%, 26.5%, and 46.9%, respectively, than in the plain tube.

Preferential freezing avoidance localised in anthers and embryo sacs in wintering Daphne kamtschatica var. jezoensis flower buds visualised by magnetic resonance imaging.

To explore diversity in cold hardiness mechanisms, high resolution magnetic resonance imaging (MRI) was used to visualise freezing behaviours in wintering Daphne kamtschatica var. jezoensis flower buds, which have naked florets and no bud scales. MRI images showed that anthers remained stably supercooled to the range from -14 to -21°C or lower while most other tissues froze by -7°C. Freezing of some anthers detected in MRI images between -14 and -21°C corresponded with numerous low temperature exotherms and also with the 'all-or-nothing' type of anther injuries. In ovules/pistils, only embryo sacs remained supercooled at -7°C or lower, but slowly dehydrated during further cooling. Cryomicroscopic observation revealed ice formation in the cavities of calyx tubes and pistils but detected no ice in embryo sacs or in anthers. The distribution of ice nucleation activity in floral tissues corroborated the tissue freezing behaviours. Filaments likely work as the ice blocking barrier that prevents ice intrusion from extracellularly frozen calyx tubes to connecting unfrozen anthers. Unique freezing behaviours were demonstrated in Daphne flower buds: preferential freezing avoidance in male and female gametophytes and their surrounding tissues (by stable supercooling in anthers and by supercooling with slow dehydration in embryo sacs) while the remaining tissues tolerate extracellular freezing.

Primulalongipilosa (Primulaceae), a new species from Yunnan, China.

Primulalongipilosa from SW Yunnan, China, is described as a species new to science and illustrated. The systematic placement of this new species is also discussed based on an nrITS molecular tree. It is morphologically most similar to P.mollis, but differs from the latter in its racemose inflorescence, green calyx tube, pink to pink rose corolla, stamens at 1/3 length above the base of the corolla tube and applanate globose capsule.

Vaccinium bangliangense, a new species of Ericaceae from limestone areas in Guangxi, China

Vacciniumbangliangense, a new species from limestone areas in Guangxi, China, is described and illustrated. It is morphologically most similar to V.pseudotonkinense and V.sciaphilum in having small and dense obovate leaf blades with a retuse apex, hairy young branches and calyx and campanulate corollas, but can be distinguished from them by the distance of basal gland from petiole, the length of peduncle, pedicle and filaments, the indumentum of calyx tube and corolla and the existence of apical glands on calyx lobes. A table to distinguish the new species from other morphologically similar Vaccinium species, as well as colour plates of comparison of key characters, is also provided.

Effects of Plant Growth Regulators on the Endogenous Hormone Content of Calyx Development in ‘Korla’ Fragrant Pear

The development of calyxes in ‘Korla’ fragrant pear is influenced by hormones. This study was conducted to investigate the effects of different plant growth regulators on the endogenous hormone content of young ‘Korla’ fragrant pear fruit. The hormone contents [indoleacetic acid (IAA), gibberellin acid (GA3), and abscisic acid (ABA)] of young ‘Korla’ pear fruits treated with water, IAA, and triiodobenzoic acid (TIBA) were determined by high-performance liquid chromatography, and the relationship between the content and ratio of endogenous hormones and calyx abscission in ‘Korla’ fragrant pear was explored. The results showed that the rate of calyx abscission in the ‘Korla’ pear fruits treated with TIBA was significantly higher than that of fruits treated with water and IAA, and that of fruits treated with water was significantly higher than that of fruits treated with IAA. The GA3 content was higher than the IAA and ABA contents during each period. The IAA content of the stalk was higher than that of the calyx tube and flesh. The GA3 and ABA contents of the calyx tube were higher than those of the stalk and flesh. The IAA and GA3 contents of the first order were higher than those of the fourth order. The ABA content of the fourth-order fruit was higher than that of the first order. The (IAA+GA3)/ABA in the calyx tube was significantly higher than that in the flesh and fruit stalk. After IAA treatment, the IAA, GA3, and ABA contents of the first-order calyx tube increased by 47.7%, 17%, and 31.6%, respectively, whereas those of the fourth-order calyx tube increased by 65.3%, 39.9%, and 33.2%, respectively. After TIBA treatment, the IAA, GA3, and ABA contents of the first-order calyx tube increased by 46.1%, 36.5%, and 50.0%, respectively, the IAA content of the fourth-order tube decreased by 25.5%, and the GA3 and ABA contents increased by 22.0% and 12.2%, respectively. The IAA, GA3, and ABA contents of the flesh and fruit stalk did not significantly differ from those in the calyx tube. The results indicated that spraying IAA during flowering promoted calyx persistence, whereas spraying TIBA promoted calyx abscission. These findings provide certain theoretical references and practical criteria for improving the quality of ‘Korla’ fragrant pear.

Short flowers for long tongues: Functional specialization in a nocturnal pollination network of an asclepiad in long‐tongued hawkmoths

AbstractSince Darwin, very long and narrow floral tubes have been known to represent the main floral morphological feature for specialized long‐tongued hawkmoth pollination. However, specialization may be driven by other contrivances instead of floral tube morphology. Asclepiads are plants with a complex floral morphology where primary hawkmoth pollination had never been described. We detailed here the intricate pollination mechanism of the South American asclepiad Schubertia grandiflora, where functional specialization on long‐tongued hawkmoth pollinators occurs despite the short floral tube of this species. We studied two plant populations in the Brazilian Cerrado and recorded floral visitors using different approaches, such as light‐trapped hawkmoths for pollen analysis, direct field observations, and IR motion‐activated cameras. Finally, using a community‐level approach we applied an ecological network analysis to identify the realized pollinator niche of S. grandiflora among the available niches in the pollinator community. Throughout a period of 17 years, long‐tongued hawkmoths were consistently recorded as the main floral visitors and the only effective pollinators of S. grandiflora. Flowers rely on highly modified corona and gynostegium, and enlarged nectar chambers, to drive visitors and pollination mechanism. Despite its relative short‐tube, network analysis placed S. grandiflora in the module including exclusively long‐tongued hawkmoth pollinators and the most phenotypically specialized sphingophilous plants in the community. These results represent the first example of functional specialization in long‐tongued hawkmoths in an asclepiad species. However, this specialization is uncoupled from the long floral tubes historically associated with the sphingophily syndrome.Abstract in Portuguese is available with online material.

A new genus of Lythraceae emerges from rocky outcrops of the Atlantic Forest in Brazil

Abstract Recent collections of Lythraceae from an isolated mountain range in eastern Brazil were found to possess a unique morphology including spurless, weakly actinomorphic floral tubes, two deep red petals, a stipitate ovary and irregularly circumscissile dehiscence of a thickened capsule, characters typically applied to taxon recognition at the generic level. Genomic DNA was extracted from herbarium specimens or silica-dried leaf tissue and subjected to Illumina sequencing, and a phylogenetic analysis was performed based on a combination of plastid trnL-trnF and rpl16 and nuclear ribosomal ITS sequences. Sequences of 22 genera of Lythraceae, including 74 Cuphea spp. representing all recognized sections of the genus and three Pleurophora spp., were included in the analysis; Ludwigia octovalvis (Onagraceae) was used to root the trees. A maximum-likelihood tree was reconstructed based on the concatenated matrix. Strong morphological evidence was found to recognize a new genus and species in Lythraceae: Gyrosphragma latipetala sp. nov., gen. nov. The same characteristics also occur in a little-known species, Cuphea santos-limae, which we transfer to Gyrosphragma. Molecular phylogenetic analysis confirms Gyrosphragma as a monophyletic genus, sister to Cuphea; together these genera form a clade with Pleurophora. The new genus, supported by morphological and molecular evidence, adds new features and extends knowledge on the ecological and geographical diversity within Lythraceae.

Structure and Development of Flowers and Inflorescences in Burmannia (Burmanniaceae, Dioscoreales).

Species of the genus Burmannia possess distinctive and highly elaborated flowers with prominent floral tubes that often bear large longitudinal wings. Complicated floral structure of Burmannia hampers understanding its floral evolutionary morphology and biology of the genus. In addition, information on structural features believed to be taxonomically important is lacking for some species. Here we provide an investigation of flowers and inflorescences of Burmannia based on a comprehensive sampling that included eight species with various lifestyles (autotrophic, partially mycoheterotrophic and mycoheterotrophic). We describe the diversity of inflorescence architecture in the genus: a basic (most likely, ancestral) inflorescence type is a thyrsoid comprising two cincinni, which is transformed into a botryoid in some species via reduction of the lateral cymes to single flowers. Burmannia oblonga differs from all the other studied species in having an adaxial (vs. transversal) floral prophyll. For the first time, we describe in detail early floral development in Burmannia. We report presence of the inner tepal lobes in B. oblonga, a species with reportedly absent inner tepals; the growth of the inner tepal lobes is arrested after the middle stage of floral development of this species, and therefore they are undetectable in a mature flower. Floral vasculature in Burmannia varies to reflect the variation of the size of the inner tepal lobes; in B. oblonga with the most reduced inner tepals their vascular supply is completely lost. The gynoecium consists of synascidiate, symplicate, and asymplicate zones. The symplicate zone is secondarily trilocular (except for its distal portion in some of the species) without visible traces of postgenital fusion, which prevented earlier researchers to correctly identify the zones within a definitive ovary. The placentas occupy the entire symplicate zone and a short distal portion of the synascidiate zone. Finally, we revealed an unexpected diversity of stamen-style interactions in Burmannia. In all species studied, the stamens are tightly arranged around the common style to occlude the flower entrance. However, in some species the stamens are free from the common style, whereas in the others the stamen connectives are postgenitally fused with the common style, which results in formation of a gynostegium.

Oreocharis hainanensis (Gesneriaceae), a new species from karst regions in Hainan Island, South China

Oreocharis hainanensis, a new species of Gesneriaceae is described and illustrated from low-altitudual karst areas in Hainan Island, South China. The new species is easily distinguished from its closely-related O. jasminina by campanulate floral tube, zygomorphic corolla and exserted stamens. It also shows different habitats from the four currently-recognized Oreocharis taxa on the island. Molecular phylogeny analysis based on plastid trnL-trnF and nuclear ITS1/2 sequences supported the delimitation of the new species, which forms a monophyletic clade with all the other Oreocharis taxa from Hainan Island. The roles of habitat and floral isolation in the evolution of the new species and its affinities are discussed. The species was assessed as Vulnerable (VU C1 and D2) according to IUCN Red List Categories and Criteria.

Parahellenia, a new genus segregated from Hellenia (Costaceae) based on phylogenetic and morphological evidence

Previous studies recognized three major lineages of the family Costaceae: a South American clade, an Asian clade and a Costus clade. However, the genus Hellenia within the Asian clade has been shown to be non-monophyletic and its morphology has not been studied carefully. Therefore, the complete plastid genomes of Hellenia species were obtained and the monophyly of Hellenia was tested through four different datasets in this study. Plastid phylogenomic analyses of Costaceae revealed that Hellenia is strongly supported as paraphyletic. Two major clades are recovered, namely the Hellenia s.s. subclade and the Parahellenia subclade. Phylogenetic analyses based on an enlarged taxon sampling of the Asian clade using a two chloroplast markers dataset (trnK intron and trnL-F spacer) confirmed the paraphyly of Hellenia. Meanwhile, morphological analyses suggested that members of the Parahellenia subclade differ from the remaining Hellenia species in many characters including inflorescences, bracts, stigma, axillary buds, floral tubes and labellum. According to the present molecular and morphological evidence, the latter subclade is recognized as a new genus, Parahellenia. Two new species are described, four new combinations are made, and identification keys are also provided.

Changing the main course: strong bat visitation to the ornithophilous mistletoe Psittacanthus robustus (Loranthaceae) in a Neotropical savanna

AbstractThe Neotropical genus Psittacanthus comprises mostly specialized ornithophilous mistletoes, with rare exceptions. Psittacanthus robustus is a common ornithophilous species from the South American savannas whose bright yellow flowers secrete copious diluted nectar. Due to a three‐day‐long anthesis and a short, non‐restrictive floral tube, we suggest that the species also serves as a resource for flower‐visiting bats. In a Cerrado area in central Brazil, we investigated the usage of the species by bats through systematic bat captures for pollen sampling, its nocturnal nectar secretion dynamics, mating system, and the relative dependence on diurnal and nocturnal pollinators for reproduction. Nine phyllostomid bat species visited P. robustus. Up to 50% of pollen samples from bats contained the species during peak flowering, equating or surpassing the prevalence of chiropterophilous species and representing roughly a third of the floral resources consumed by specialized nectarivores Glossophaga soricina and Anoura caudifer. Flowers actively produced nectar at night with volume and concentration values in the ideal ranges for bat consumption. Nectar is continuously secreted after sunset and accumulates in the absence of visitors. Psittacanthus robustus is self‐compatible but seeds are set mostly by diurnal visitors. Nocturnal animals had a low and secondary contribution to plant fitness. This is the second report of bat pollination for the genus Psittacanthus, and the largest assemblage of bat visitors for the family Loranthaceae. Although ornithophilous, P. robustus is an important resource for bats in the Brazilian savanna, potentially representing a mixed or early transitional state toward bat pollination.Abstract in Portuguese is available with online material.