The systematic relevance of fruit and seed anatomy and morphology of Akania (Akaniaceae)

The fruit and seed anatomy and morphology of Akania bidwillii , the monotypic genus in the Akaniaceae, have been studied in an effort to clarify its systematic position. The loculicidal (1,2-) 3-locular fruit with Ugnified fibrous 6–7-layered endocarp is clearly of capsular type. Seeds of Akania are relatively large, smelling of bitter almonds, abundantly albuminous, with straight dicotyledonous embryo. The seed coat of Akania is exo-mesotestal with fully obliterated tegmen in early stages; 1-layered exotesta represented by columellar thick-walled cells with numerous invaginations of inner cell walls; mesotesta 25–35-layered, composed of thick-walled, but not lignified mostly rounded sclereids filled with tanninlike substances, the innermost part of mesotesta is aerenchymatous, sometimes collapsed, and traversed by 6(8) postchalazal vascular bundles, 2–3 layers of endotesta composed of enlarged cuboid cells with heavily thickened walls. Evidence mainly from seed morphology and anatomy of seed coats emphasizes the anomaly of the traditional inclusion of Ankaniaceae in the Sapindales, being quite distinct in spermoderm structure and origin from both Sapindaceae and Staphyleaceae in particular as well as from other families of the order, excepting somewhat anomalous exo-mesotestal Bretschneideraceae. Furthermore, seed anatomy does not confirm any relationships with Capparales. It is suggested that Akaniaceae together with Bretschneideraceae constitute a distinct relict side-branch of connaraceous-sapindaceous ancestry tracing back to primitive exo-mesotestal Resales. On the basis of available data of seed coat anatomy it is appropriate to remove archaic Akaniaceae with Bretschneideraceae from more advanced Sapindales. Furthermore, widi the addition of more data on carpology and seed anatomy of basal Rosidae the systematic position of the family should be redefined in terms of its primitiveness and the lack of close relationships with Sapindales.     

Ovules and seeds in Acalyphoideae (Euphorbiaceae): structure and systematic implications

Acalyphoideae, the largest subfamily of Euphorbiaceae, are investigated with respect to ovule and seed structure on the basis of 172 species of 80 genera in all 20 tribes of Acalyphoideae sensu Webster. All species of Acalyphoideae examined have bitegmic ovules with a non-vascularized inner integument. However, noticeable differences exist among and sometimes within the genera in the thickness of the inner and outer integument, the presence or absence of vascular bundles in the outer integument, whether ovules are pachychalazal or not, the presence or absence of an aril, seed coat structure (in terms of the best-developed mechanical cell-layer), and the shape of cells constituting the exotegmen. For the latter two characters, two different types of seed coat (i.e., "exotegmic" and "exotestal") and three different types of exotegmic cell (i.e., palisadal, tracheoidal and ribbon-like) were distinguished. Comparisons showed that three tribes Clutieae, Chaetocarpeae and Pereae are distinct from the other Acalyphoideae as well as from the other Euphorbiaceae in having an exotestal seed coat with a tracheoidal exotegmen. The tribe Dicoelieae is also distinct from the other Acalyphoideae in having an exotegmic seed that is composed of ribbon-like cells of exotegmen (i.e., cells both longitudinally and radially elongated, sclerotic and pitted). The tribe Galearieae, which should be treated as a distinct family Pandaceae, is also distinct from the other Acalyphoideae in having an exotegmic seed with a tracheoidal exotegmen (i.e., cells longitudinally elongated, sclerotic and pitted). The remaining genera of Acalyphoideae always have an exotegmic seed with a palisadal exotegmen (i.e., cells radially elongated, sclerotic and pitted). The shared palisadal exotegmen supports the close affinity of Acalyphoideae (excluding five tribes) with Crotonoideae and Euphorbioideae. Within the remaining genera of Acalyphoideae, a significant diversity is found in ovule and seed morphology with respect to the thickness of the inner and outer integument, the size of chalaza, vascularization of an outer integument and an aril.     

First Miocene fossils of Vivianiaceae shed new light on phylogeny,divergence times,and historical biogeography of Geraniales

The origin of Geraniales (approximately 900 species in three families: Geraniaceae, Melianthaceae, and Vivianiaceae) is traced back to the Cretaceous of Gondwana, yet their geotemporal history is largely unknown because of a limited fossil record and incomplete phylogenies. In the present study, we provide the first fossil record of Vivianiaceae and a highly resolved molecular phylogeny for all extant Geraniales genera. Our results support the hypothesis that five (instead of three) families should be recognized in the order Geraniales: Francoaceae A. Juss. (Francoa, Greyia, Tetilla), Geraniaceae Juss. (Erodium, Geranium, Monsonia, Pelargonium), Hypseocharitaceae Wedd. (monogeneric), Melianthaceae Horan. (Bersama, Melianthus), and Vivianiaceae Klotzsch (Balbisia, Rhynchotheca, Viviania). The four major lineages (i.e. Geraniaceae, Francoaceae + Melianthaceae, Hypseocharitaceae, Vivianiaceae) all originated within a narrow time frame during the Eocene (36.9–49.9 Mya) based on the five fossil calibration points. The divergence of most of the extant genera occurred much later, from the Miocene onwards. The South American–South African disjunction in Francoaceae apparently goes back to long distance dispersal with an estimated divergence time of the lineages in the Middle Miocene [11.2 (5.9–17.7) Mya]. Diversification in Melianthus appears to be much more recent than previously assumed [starting approximately 3.4 (1.9–5.2) Mya rather than approximately 8–20 Mya]. However, divergence of the Andean Hypseocharis lineage [36.9 (31.9–42.8) Mya] significantly predates the main Andean uplift: Current distributions likely go back to northward migrations and subsequent extinctions in Patagonia. Similarly, Rhynchotheca, Balbisia, and Viviania have a current southern distribution limit > 10°N of the fossil finds, indicating a massive northward displacement. The present evidence suggests that niche conservatism likely played a major role in the historical biogeography of Geraniales. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Floral development and anatomy of Dirachma socotrana, (Dirachmaceae): a controversial member of the Rosales

The floral development and anatomy of Dirachma has been investigated with SEM and LM to discuss the relationship of Dirachmaceae with putative sister taxa (e.g. Rhamnaceae, Malvaceae, Barbeyaceae, Elaeagnaceae) on the basis of morphological synapomorphies. Flowers are initiated in axillary position on terminal branches. An epicalyx consisting of six to eight bracteoles surrounds the valvate calyx. Petal initiation is strongly retarded and primordia arise independently opposite the stamen primordia. The carpels arise independently and become weakly fused at the base; a single ovule develops in an axile position. A hypanthium develops by interprimordial growth between petals and stamens. Nectaries arise in a pouch and are covered with trichomes positioned on a protuberance at the base of the petal. It is suggested that the solitary flowers are derived from compound cymose inflorescences. Comparison between Dirachma and species of Rhamnaceae demonstrates striking similarities in floral structure and anatomy. However, several characters are unique to Dirachma and support a family Dirachmaceae separate from Rhamnaceae.We thank Frieda Christie for technical assistance with the SEM and LM preparations. We very much appreciate the constructive comments of Peter Endress and Paula Rudall.     

The embryology and taxonomic relationships of Bretschneidera (Bretschneideraceae)

TOBE, H. & PENG, C.-I, 1990. The embryology and taxonomic relationships of Bretschneidera (Bretschneideraceae). We present the first report on the embryology of Bretschneidera , the only genus of Bretschneideraceae (which are one of 15 glucosinolate-producing families), to clarify its relationships. Embryologically Bretschneidera is characterized by the following features: ovule campylotropous, bitegmic and crassinucellate; outer integument thick, multiplicative and vascularized; embryo sac formation of the Allium type; seed exalbuminous; seed coat 'exotestal' with a palisade of columellar, thick-walled exotestal cells; mesotesta thick with the inner half aerenchymatous. These features suggest that Bretschneidera is distinct from any of the taxonomically related families but resembles both Hippocastanaceae and Sapindaceae (Sapindales) more closely than Moringaceae or Capparaceae (Capparales) which have been considered alternative allies, supporting most of the modern taxonomic treatments that place Bretschneidera as a separate family in Sapindales.     

Infectivity and effectivity of Frankia strains from the Rhamnaceae family on different actinorhizal plants

Ten strains of Frankia isolated from root nodules of plant species from five genera of the host family Rhamnaceae were assayed in cross inoculation assays. They were tested on host plants belonging to four actinorhizal families: Trevoa trinervis (Rhamnaceae), Elaeagnus angustifolia (Elaeagnaceae), Alnus glutinosa (Betulaceae) and Casuarina cunninghamiana (Casuarinaceae). All Frankia strains from the Rhamnaceae were able to infect and nodulate both T. trinervis and E. angustifolia. Strain ChI4 isolated from Colletia hystrix was also infective on Alnus glutinosa. All nodules showed a positive acetylene reduction indicating that the microsymbionts used as inoculants were effective in nitrogen fixation. The results suggest that Frankia strains from Rhamnaceae belong to the Elaeagnus-infective subdivision of the genus Frankia.     

Evolution of fruit and seed characters in the Diervilla and Lonicera clades (Caprifoliaceae, Dipsacales)

Background and Aims

The Diervilla and Lonicera clades are members of the family Caprifoliaceae (Dipsacales sensu Donoghue et al., 2001, Harvard Papers in Botany 6: 459–479). So far, the intergeneric relationships of the Lonicera clade and the systematic position of Heptacodium remain equivocal. By studying fruit and seed morphology and anatomy, an attempt is made to clarify these issues. In addition, this study deals with the evolution of fruit and seed characters of the Diervilla and Lonicera clades with reference to allied taxa.

Methods

Light and scanning electron microscopy were used for the morphological and anatomical investigations. Phylogenetic analyses were carried out by applying the parsimony and Bayesian inference optimality criteria. Character evolution was studied by means of parsimony optimization and stochastic character mapping.

Key Results

Diervilla and Weigela (Diervilla clade) are characterized by several unique traits in Dipsacales, including capsules with numerous seeds, seed coats without sclerified outer tangential exotestal cell walls, and dehiscent fruits. Seeds with completely sclerified exotestal cells and fleshy fruits characterize the Lonicera clade. Leycesteria and Lonicera have berries, ovaries without sterile carpels and several seeds per locule, whereas Symphoricarpos and Triosteum have drupes, ovaries with one or two sterile carpels and a single seed per locule. Heptacodium shares several characteristics with members of the Linnina clade, e.g. achenes, single-seeded fruits and a compressed, parenchymatous seed coat.

Conclusions

The results confirm the monophyly of the Diervilla and Lonicera clades and allow us to hypothesize a close relationship between Leycesteria and Lonicera and between Symphoricarpos and Triosteum. Fruit and seed morphology and anatomy point to a sister relationship of Heptacodium with the Linnina clade, rather than with the Lonicera clade.Key words: Diervilla, Weigela, Symphoricarpos, Lonicera, Triosteum, Leycesteria, Heptacodium, Caprifoliaceae, Dipsacales, fruit, seed, evolution     

Phylogenetic relationships of Coreanomecon (Papaveraceae: Chelidonioideae) inferred from seed morphology and nrITS sequence data

The phylogenetic position of the Coreanomecon, a monotypic genus endemic to Korea, has been controversial for a long time. Coreanomecon has variously been placed in its own genus or combined with Hylomecon or Chelidonium. The main purpose of this study was to examine the phylogenetic position of Coreanomecon in relation to genera of the subfamily Chelidonioideae using seed morphology and molecular data. The seed morphology of 10 genera of Chelidonioideae was examined using microtome sections and scanning electron microscopy. The shape and size of exotestal cells varied between genera. The exotestal cells were tangentially elongated in Chelidonium majus, Stylophorum diphyllum and Hylomecon vernalis, whereas the cells were sub‐orbicular and broad in Coreanomecon hylomeconoides. The endotesta was represented by thick palisade‐like cells that contain small rectangular crystals near their outer walls. The mesotesta was totally collapsed in Co. hylomeconoides but wholly or partly persistent in Ch. majus and H. vernalis. The seed surface of Co. hylomeconoides was well ornamented with a unique echinate seed surface, whereas other genera showed plain and reticulate seed surfaces. A phylogenetic analysis of the genera including Coreanomecon was conducted with nuclear ribosomal internal transcribed spacer (nrITS) sequences using genetic distance, maximum parsimony, maximum likelihood and Bayesian inference methods. The results confirm that Co. hylomeconoides is separated from both Hylomecon species and is a sister group to Chelidonium majus and Stylophorum diphyllum with robust bootstrap support. In addition to differences in the absence of cauline leaves and rhizomes, the presence of a hairy stem and leaves, and 12‐pericolpate pollen, seed characters and molecular data strongly support the recognition of Coreanomecon as an independent genus, distinct from Hylomecon and Chelidonium.     

Seed coat anatomy ofCrossostylis (Rhizophoraceae): its evolutionary and systematic implications

The seed coat structure of all 13 species ofCrossostylis was studied to contribute to an understanding of species delimitation and relationships within the genus. The mature seed coat is relatively uniform and consistently constructed mainly by a well-developed exotesta and a well-developed fibrous exotegmen. The species differ in the thickness of the exotesta and exotegmen, the anatomy of exotestal cells, the presence and absence of persistent mesotesta, and so forth. On the basis of comparisons of these characters, close relationships are suggested in the species groups such as:Crossostylis banksiana andC. cominsii; C. biflora, C. raiateensis andC. multiflora; C. gandiflora, C. sebertii andC. imera; and five species in the Fiji Islands. These relationships except for those of Fijian five species are also supported by cladistics as their common characters are evaluated as synapomorphy. Species-level separation ofC. banksiana, C. pedunculata andC. raiateensis each from the closest species is doubted based on the results of seed coat structure.     

Sapindales: molecular delimitation and infraordinal groups

An analysis of rbcL sequence data for representatives of families of putative sapindalean/rutalean affinity identified a robust clade of core “sapindalean” taxa that is sister to representatives of Malvales. The constitution of this clade approximates the broad concept of Sapindales (sensu Cronquist). Five lineages within the order are recognized: a “rutaceae” clade (Rutaceae, Cneoraceae, Ptaeroxylaceae, Simaroubaceae sensu stricto, and Meliaceae); a “sapindaceae” clade (Sapindaceae, Aceraceae, and Hippocastenaceae); Anacardiaceae plus Burseraceae; Kirkiaceae; and Zygophyllaceae pro parte. Relationships among these groups were only weakly resolved, but there was no support for the recognition of the two more narrowly defined orders, Rutales and Sapindales sensu stricto. Several families that have previously been allied to Sapindales or Rutales show no affinity to the core sapindalean taxa identified with the molecular data, and are excluded from the order: viz. Akaniaceae, Bretschneideraceae, Conneraceae, Coriariaceae, Melianthaceae, Meliosmaceae, Physenaceae, Rhabdodrendraceae, Sabiaceae, Staphyleaceae, Stylobasiaceae, Surianaceae, and Zygophyllaceae sensu stricto.     

THE DELIMITATION OF BIGNONIACEAE AND SCROPHULARIACEAE BASED ON FLORAL ANATOMY,AND THE PLACEMENT OF PROBLEM GENERA

The delimitation of Bignoniaceae and Scrophulariaceae has long been a taxonomic problem. Several genera, including Paulownia, Schlegelia, Gibsoniothamnus, and Synapsis, have been variously placed in one or the other family. Differences between these two families have been noted with regard to the presence of endosperm, embryo and seed morphology, and placentation; however, the lack of comprehensive data on the distribution of such characters within these two families left the delimitation problem unsolved. A comprehensive study of floral anatomy confirmed a basic difference in the placentation of these two families, as well as a basic difference in gynoecial vascularization. Paulownia has a floral anatomy, embryo morphology, and seed morphology consistent with placement in Scrophulariaceae. While reminiscent of Bignoniaceae, Paulownia is not an intermediate genus linking the two families. Schlegelia and Gibsoniothamnus have a floral anatomy consistent with placement in Scrophulariaceae. Schlegelia also has a scrophulariaceous seed morphology. Considered anomalous in the Bignoniaceae, the Schlegelieae similarly are distinct in the Scrophulariaceae.     

COMPARATIVE FLOWER AND FRUIT MORPHOGENESIS IN COLUBRINA (RHAMNACEAE) WITH SPECIAL REFERENCE TO C. ASIATICA

Flower and fruit morphogenesis of Colubrina asiatica, including aspects of fruit dehiscence and seed morphology, were studied by scanning electron microscopy and serial sectioning. Material from 13 additional species representing most intrageneric diversity was also examined. Organ initiation is simultaneous within each floral whorl and proceeds centripetally. Each petal/stamen pair apparently arises by tangential splitting of an individual primordium. The ontogeny of the three-locular, semi-inferior gynoecium follows a pattern common to many Rhamnaceae. At anthesis each uniovulated carpel has an almost independent pollen-tube pathway, with a subbasal compitum allowing for interconnection between carpels. Protandry, herkogamy, and a tendency to polygamy seemed to occur in C. asiatica. Fruit growth results mainly from postfloral promotion of the previously negligible superior part of the ovary. The explosively to tardily dehiscent capsules include three thin-walled, dehiscent stones (endocarpids) of inner dermal origin. At maturity, xerochastic (i.e., caused by desiccation), oblique bending of the endocarpids generates a complex dehiscence pattern involving thorough breaking of epicarp and mesocarp. The Colubrina type of fruit may be considered basic within the Rhamnaceae, which is consistent with the putative primitiveness of the genus. A limited potential for specialization is, however, expressed in such traits as explosive dehiscence, persistent arils on the seeds, and dispersal by sea currents (thalassochory).     

The Chloroplast Genome of Elaeagnus macrophylla and trnH Duplication Event in Elaeagnaceae

Elaeagnaceae, which harbor nitrogen-fixing actinomycetes, is a plant family of the Rosales and sister to Rhamnaceae, Barbeyaceae and Dirachmaceae. The results of previous molecular studies have not strongly supported the families of Elaeagnaceae, Rhamnaceae, Barbeyaceae and Dirachmaceae. However, chloroplast genome studies provide valuable phylogenetic information; therefore, we determined the chloroplast genome of Elaeaganus macrophylla and compared it to that of Rosales such as IR junction and infA gene. The chloroplast genome of Elaeagnus macrophylla is 152,224 bp in length and the infA gene of E. macrophylla was psuedogenation. Phylogenetic analyses based on 79 genes in 30 species revealed that Elaeagnus was closely related to Morus. Comparison of the IR junction in six other rosids revealed that the trnH gene contained the LSC region, whereas E. macrophylla contained a trnH gene duplication in the IR region. Comparison of the LSC/IRb (J_LB) and the IRa/LSC (J_LA) regions of Elaeagnaceae (Elaeagnus and Shephedia) and Rhamnaceae (Rhamnus) showed that trnH gene duplication only occurred in the Elaeagnaceae. The complete chloroplast genome of Elaeagnus macrophylla provides unique characteristics in rosids. The infA gene has been lost or transferred to the nucleus in rosids, while E. macrophylla lost the infA gene. Evaluation of the chloroplast genome of Elaeagnus revealed trnH gene duplication for the first time in rosids. The availability of Elaeagnus cp genomes provides valuable information describing the relationship of Elaeagnaceae, Barbeyaceae and Dirachmaceae, IR junction that will be valuable to future systematics studies.     

Two new species ofPhyllagathis related toP. tuberculata (Melastomataceae) from Peninsular Malaysia

Phyllagathis tuberculata King and two closely allied new species,P. magnifica A. Weber andP. stonei A. Weber, are described and illustrated. Within the genus, these species form a distinct and isolated group which is restricted to Peninsular Malaysia.P. tuberculata occurs in Perak (probably confined to G. Bujang Melaka),P. magnifica andP. stonei are found in the mountains on the Pahang/Selangor border (Genting Highlands, Gombak valley). The distinctive characters of the three species are listed and some general information relating to inflorescence morphology, tubercle anatomy, fruit structure and seed dispersal is provided.     

Diversity of Frankia Strains in Root Nodules of Plants from the Families Elaeagnaceae and Rhamnaceae

Partial 16S ribosomal DNAs (rDNAs) were PCR amplified and sequenced from Frankia strains living in root nodules of plants belonging to the families Elaeagnaceae and Rhamnaceae, including Colletia hystrix, Elaeagnus angustifolia, an unidentified Elaeagnus sp., Talguenea quinquenervia, and Trevoa trinervis. Nearly full-length 16S rDNAs were sequenced from strains of Frankia living in nodules of Ceanothus americanus, C. hystrix, Coriaria arborea, and Trevoa trinervis. Partial sequences also were obtained from Frankia strains isolated and cultured from the nodules of C. hystrix, Discaria serratifolia, D. trinervis, Retanilla ephedra, T. quinquenervia, and T. trinervis (Rhamnaceae). Comparison of these sequences and other published sequences of Frankia 16S rDNA reveals that the microsymbionts and isolated strains from the two plant families form a distinct phylogenetic clade, except for those from C. americanus. All sequences in the clade have a common 2-base deletion compared with other Frankia strains. Sequences from C. americanus nodules lack the deletion and cluster with Frankia strains infecting plants of the family Rosaceae. Published plant phylogenies (based on chloroplast rbcL sequences) group the members of the families Elaeagnaceae and Rhamnaceae together in the same clade. Thus, with the exception of C. americanus, actinorhizal plants of these families and their Frankia microsymbionts share a common symbiotic origin.     

Wood anatomy of Elaeagnaceae, with comments on vestured pits, helical thickenings, and systematic relationships

The secondary xylem of Elaeagnus, Hippophae, and Shepherdia is described and illustrated in detail. Shrubs and small trees of Elaeagnaceae have ring-porous or semi-ring-porous wood with simple perforation plates, vascular tracheids, fiber-tracheids, diffuse or rarely paratracheal axial parenchyma, and uni- or biseriate rays in Hippophae and Shepherdia, but wider rays in Elaeagnus. Walls of vessel elements, especially narrow ones, tracheids, or fiber-tracheids sometimes show helical thickenings; in a few instances these intergrade with small bud-like protrusions associated with pits. Scanning electron microscopy illustrates that small to vestigial vestures are present in all species studied, although nonvestured pits are also common. The analogous nature of vestures and helical thickenings is considered. Comparative wood anatomy suggests a rather isolated position of the family Elaeagnaceae; affinities with Rhamnaceae, Proteaceae, and Thymelaeaceae are discussed.     

Analysis of sexual polymorphism of the plant from subclass Rosidae in Siberia

Sexual systems and association with several ecological and life history attributes were examined for 977 native angiosperms of subclass Rosidae in Siberia. The majority of angiosperms in Siberia are hermaphrodites (87.7%, N = 867). The most widespread forms of sexual differentiations are andromonoecy, gynodioecy, and dioecy. The rarest forms of sexual differentiations are monoecy, trioecy, and androdioecy. Seven of 34 families are the richest in species with sexual differentiation: Aceraceae, Elaeagnaceae, Haloragaceae, Rhamnaceae, Dipsacaceae, Apiaceae, and Geraniaceae.     

星油藤蒴果及种子的性状变异研究

为进行星油藤(Plukenetia volubilis L.)良种选育,对其蒴果和种子的性状变异进行了研究。结果表明,星油藤蒴果中4、5、6裂片果分别为49.71%、37.69%和12.60%,以4和5裂片为主;种子性状变异系数比果实的小,种子性状比果实更稳定。按果裂片类型统计,以4裂片的性状变异系数最小,性状也较为稳定,性状分化变异率有54.19%~95.63%来自蒴果间,而果实和种子性状分化变异率分别有79.81%~95.76%和67.66%~93.0%来源于裂片类型,性状分化变异受裂片数影响大,而相同裂片数不同蒴果间的变异程度低。不同裂片类型的果实与种子大多数性状间均存在显著或极显著差异,果裂数是造成性状差异的主要原因。种子萌发率以6裂片果5裂片果4裂片果,平均萌发率超过91%;种子萌发率与单果重、单果重与果形态指标、种子重与种子形态性状间均存在极显著正相关关系,其中单果重对果厚、种子重对种子宽的影响大于其它性状。综合分析星油藤以4裂片果的生物产量最高,平均果重和种子重均好于其他类型。