Leaf anatomy of the subtribe Hyptidinae (Labiatae)

The leaf anatomy of the subtribe Hyptidinae (Labiatae), which consists of four small genera and the largr genus Hyplis , is dercribed. The leaves may be dorsiventral or isobilateral. Variable characters of the lainina include: frequency and forms of trichomes, cuticular markings, presence of adaxial stoinata, thickness of leaf, thickness of adaxial epidermis, presence of a hypodermis, occurrence of sclcrified tissues (especially sclerified bundle sheath extensions, phloem and xylem fibres), mesophyll structure and venation pattern. Petiole vasculature varies from simple to complex, sometimes with medullary traces present. Most of the variable characters are related to xeromorphy and are tax-onomically useful within the framework of the present classification.     

Flower anatomy of the subtribe Hyptidinae (Labiatae)

Flowers of 34 species, representing 4 of the 6 genera of the morphologically diverse South American subtribe Hyptidinae and including members of many of the sections of the genus Hyptis are investigated. Floral anatomy is basically uniform, with some minor variations which are mainly related to differences in flower size. Marsypianthes differs from the other genera in that the style is fused to the ovary, the hypogynous disc is relatively massive, and there are 12 or 13 calyx traces rather than the usual number of 10. The stylopodium, which is characteristic of Eriope and certain sections of Hyptis, is a fold of stylar tissue which develops in the bud prior to opening of the flower and is probably an abscission layer.     

Vegetative anatomy of subtribe Habenariinae (Orchidaceae)

Leaves of Habenariinae are characterized by anomocytic stomatal apparatuses, homogeneous mesophyll, collateral vascular bundles in a single series, and thin-walled bundle sheath cells. There is no foliar sclerenchyma nor a hypodermis. Cauline cortex consists of thin-walled living cells among which are large and numerous intercellular spaces. The ground tissue is bordered externally by a layer of thick-walled living cells, except in Habenaria repens. Central ground tissue cells are living, and usually thin-walled surrounding intercellular spaces of various dimensions. These are conspicuously large in H. repens. Collateral vascular bundles are scattered across the ground tissue. Sclerenchyma is absent. Absorbing roots are generally velamentous, exodermal dead cells are diin-walled, and passage cells usually have a thickened outer wall. A regular vascular cylinder is present, and vascular tissue is embedded in parenchyma. Root tubers are velamentous, exodermal cells are usually thin-walled, and passage cells frequently have thickened outer walls. Vascular tissue of root tubers is organized into two classes: (1) those with a single vascular cylinder surrounded by a cortex and (2) those with a series of meristeles dispersed throughout the ground tissue. In group (1) cortex is homogeneous either with or without mucilage cells except in Stenoglattis where the cortex is heterogeneous, consisting of water-storage and assimilatory cells, and lacks mucilage cells. In group (2) the ground tissue consists of larger mucilage-containing cells and smaller assimilatory cells.     

Vegetative anatomy of subtribe Orchidinae (Orchidaceae)

Leaves in Orchidinae are essentially glabrous; anticlinal walls of foliar epidermal cells arc basically straight-sided to curvilinear, and cells arc fundamentally polygonal on both surfaces; adaxial cells are larger than abaxial cells. Stomata arc anomocytic and usually only abaxial and superficial; substomatal chambers are small to moderate; outer and inner guard cell ledges are mostly small. There is no hypodermis nor are there fibre bundles. Mesophyll is homogeneous, chlorcnchyma cells arc thin-walled, and intercellular spaces numerous. Crystalliferous idioblasts abound. Vascular bundles are collateral, organized in a single series. and lack associated sclerenchyma. Bundle sheath cells are thin-walled and chlorophyllous. Stems are glabrous; stomata arc frequent in one species, lacking in others. Cortical cells are oval to circular, thick-walled, and interspersed with triangular intercellular spaces. Ground-tissue cells are circular, and triangular intercellular spaces are present. Vascular bundles arc collateral and scattered throughout the ground-tissue or are absent from the central ground-tissue. Epidermis in absorbing roots is one-layered and non-velamcntous. Exodcrmal cells are thin-walled and dead cell walls bear tenuous scalariform bars; some species lack an exodermis. Outer cortical cells are polygonal and lack intercellular spaces; middle layer cortical cells are rounded with triangular intercellular spaces; inner layer cells are polygonal and lack intercellular spaces. Endodermis and pericycle are thin-walled and one-layered. Vascular cylinder is mostly 7–9-arch with xylcm and phloem components alternating regularly; vascular tissue is embedded in parenchyma; pith cells are parenchymatous, polygonal, thin-walled and lack intercellular spaces. Root tubers generally bear a velamen of variable thickness; bulbous-based unicellular hairs frequently form a dense mat; exodermal cells are thin-walled; dead cells have scalariform bars, passage cells are sparse. Ground-tissue consists of rounded water-storage and assimilatory cells interspersed with triangular or quadrangular intercellular spaces; peripheral cells arc polygonal lacking intercellular spaces. Vascular tissue consists of monarch to pentarch meristeles distributed thoughout the ground-tissue each surrounded by a uniscriale endodermis of thin-walled cells. Thin roots ofPlalanthera exhibit a typical central cylinder surrounded by a homogeneous cortex uninterrupted by meristeles; thicker roots show a central vascular cylinder and cortex in which meristeles are also present; in globoid root tubers there is no central cylinder, and the ground-tissue is replete with scattered meristeles. Because the central vascular cylinder in Platanthera gives rise to branches (meristeles), these represent components of a single vascular system and are not separate stelar entities as implied by the use of the term ‘polystele’.     

Vegetative anatomy and systematics of subtribe Dendrobiinae (Orchidaceae)

Anatomy of leaf, stem, and root of more than 100 species in subtribe Dendrobiinae (Orchidaceae) was studied with the light microscope to provide a comparative anatomical treatment of these organs, to serve as an independent source of evidence that might be taxonomically important, and to recommend such reinterpretations of existing classifications as are suggested by a phylogenetic assessment of data. We based our classification on that of Rudolf Schlechter as the most complete and widely accepted today. We found that the anatomy of plants in subtribe Dendrobiinae reflects a high degree of morphological diversity, and many of the anatomical characters appear to be homoplasous. When these anatomical data are used to interpret the systematic relationships among the genera, they indicate that Dendrobium is not monophyletic and that Cadetia and Pseuderia are apparently nested within the structure of Dendrobium when section Grastidium is chosen as a functional outgroup. Lack of resolution in the strict consensus tree illustrates the difficulty of determining the phylogenetic relationships of many of Schlechter's sections using anatomical characters. Nevertheless, we recommend that his sectional classification, with appropriate modifications based on available data, be retained for the present, pending a more detailed understanding of the phylogeny of Dendrobiinae based on morphology, micromorphology, anatomy, and DNA studies.     

Pollen morphology and systematics of palaeotropical Phyllanthus and related genera of subtribe Phyllanthinae (Euphorbiaceae)

The observations of pollen from 27 species of subtribe Phyllanthinae using scanning electron microscopy reveal considerable morphological diversity in palaeotropical Phyllanthus and the related palaeotropical genera Breynia, Glochidion, and Sauropus. The tribe appears to be monophyletic, but the pollen morphology does not support the monophyly of Phyllanthus or Sauropus. Within Phyllanthus, the pollen characters suggest a close relationship between the subgenera Emblica and Phyllanthodendron. They also reveal a surprising morphological congruence between the pollen grains of section Ceramanthus (subgenus Isocladus) and those of subgenus Eriococcus, although it is not clear whether this similarity is homoplastic. The presence of diploporate colpi is a synapomorphy uniting Breynia and Sauropus, but may be homoplastic in Phyllanthus. The affinities suggested by the morphological features of the pollen in the Phyllanthinae are concordant with recent molecular phylogenies. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 591–608.     

Leaf anatomy inTigridieae (Iridaceae)

A biometric study of theSarcocapnos crassifolia complex from eastern Andalusia (Spain), Algeria, and Morocco was carried out. Twentytwo populations were used in a principal components analysis based on 14 variables. The results support the recognition of two species,S. crassifolia andS. pulcherrima, spec. nova. The taxon described byBoissier asS. speciosa (S. crassifolia subsp.Speciosa) is maintained inS. crassifolia.     

Leaf anatomy plasticity of Alchornea triplinervia (Euphorbiaceae) under distinct light regimes in a Brazilian montane Atlantic rain forest

 Alchornea triplinervia trees occur in a montane Atlantic rainforest at the Macaé de Cima State Ecological Reserve (Nova Friburgo, RJ, Brazil). They are found in two adjacent secondary forests at distinct successional stages: a late-secondary (shaded and humid) and an early-secondary forest (drier, higher light intensities reaching the understory). Leaf samples collected in these environments were compared in regard to various anatomic parameters. Histochemical tests, anatomic measurements and counting indicated no significant variation for the basic leaf anatomy. Nevertheless, as compared to the late-secondary forest, the leaves of the early-secondary forest individuals showed an increased bulk of sclerenchyma at the main nervation and petiole, gelatinous fibers with hygroscopic walls all along the central vascular system, thicker cuticle, a higher abaxial stomatal density, abundance of tannin in the mesophyll, a significantly thicker palisade and spongy parenchyma, and compactation of the spongy parenchyma. This anatomical variation indicates an increased xeromorphism of leaves under the drier conditions of the early-secondary forest. Leaf anatomy plasticity may contribute to the high ecological plasticity of this widespread neotropical species. Received: 11 November 1996 / Accepted: 5 February 1997     

Bark anatomy in Croton draco var. draco (Euphorbiaceae)

Many arboreal forms of the genus Croton (ca. 800 spp.), amply distributed in the Americas, have latex-producing cells in their bark, which is widely used in traditional medicine to treat skin infections and some forms of cancer. Studies validate its ethnomedicinal use-more than 20 pharmaceutically important secondary metabolites have been reported for its latex and bark-but anatomical and ecological studies are scarce. Given this species' ample distribution, laticifer abundance could be affected by the environment. We tested this for genetically similar trees growing in two types of vegetation in Veracruz, Mexico at sites commonly visited by traditional doctors. We describe the bark anatomy of C. draco, focusing on the laticifers, histochemically characterize the bark and the latex extracted from it, and document differences in laticifer abundance in the two environments. We have also identified another cell type (what we call type B) in the secretory latex system and describe it histochemically and microscopically. The location of bark cells that contain essential oils is reported here for the first time. Given the genetic similarity of the trees at both sites, the between-site variation in the number of laticifers in stem and branch bark appears to be an effect of the environment.     

国产木兰科含笑亚族植物的叶结构及其分类学意义

为了探讨含笑亚族Micheliinae植物属间关系以及含笑属Michella属下等级的划分和一些种的分类学地位,利用放大镜和体视镜对国产含笑亚族植物3属共28个分类群的叶结构特征进行了观察与研究。结果表明：含笑属、合果木属Paramichelia和观光木属Tsoongiodendron植物的脉序类型、一级脉、二级脉及其间脉和三级脉等特征表现出较高的一致性,三属间无明显的划分界限;但是,盲脉及其分支、网眼的发育和大小、叶缘末级脉等叶结构特征存在种间差异。在含笑属中,树状盲脉首次被观察到。用UPGMA对所研究28个分类群、木兰属Magnolia两个亚属各2种和鹅掌楸Liriodendron chinense的叶结构特征和形态学特征共46个性状进行聚类分析。分析结果表明：（1）合果木Pbaillonii和观光木T.odorum与含笑属的种聚为一支,因此,支持将合果木属和观光木属归并入含笑属;（2）这些特征为含笑属内组的划分提供了分类学意义;（3）基于叶结构特征、形态学特征、地理分布、聚类分析,对含笑属内一些种类的分类地位进行了讨论。     

Leaf flavonoids from Croton urucurana and C. floribundus (Euphorbiaceae)

Flavonoids were isolated by PVPP column chromatography of leaf extracts of Croton floribundus Spreng and C. urucurana Baill. and identified by NMR and co-chromatography with standards. The two species revealed highly distinct flavonoid profiles. C. urucurana, belonging to the phylogenetically basal section Cyclostigma, yielded the flavone C-glycosides vitexin and orientin, quercetin and the O-glycosides quercetin 7-O-rhamnoside, rhamnitrin and rutin, in addition to tiliroside. Instead, C. floribundus, from the more derived section Lasiogyne, yielded no C-glycosides, but a high diversity of classes of flavonols, including kaempferol, three flavonol O-methyl ethers, isoquercitrin, three tri-O-galactosides, in addition to tiliroside and an isorhamnetin-coumaroyl-O-glycoside. The present work is the first report for Croton of two rhamnosides (isolated from C. urucurana). It is also the first report for Euphorbiaceae of two tri-O-glycosides obtained from C. floribundus. The distribution of flavonoids in the two species as determined by HPLC-DAD of extracts of small leaf samples of herbarium specimens is highly similar with the profiles resulting from isolation of compounds from bulky leaf samples. Differences among specimens of the same species were restricted to relative proportions of individual constituents. The results indicate that flavonoid profiles are effective to characterize and distinguish the two species. The present results, combined with literature data, supports the condition of tiliroside as a marker of Croton and the hypothesis of an evolutionary trend in the genus toward the loss of C-glycosides and a progressive complexity of flavonoid profiles.     

Leaf anatomy and relationships of Dietes (Iridaceae)

The leaf anatomy of Dietes is described, including all 6 species. Characters support the morphological evidence that Dietes is a distinct genus and related to other Iridoideae. Certain features, notably the epidermal structure and sheath vasculature, distinguish it from other Iridaceous genera, although the sheath vasculature indicates a relationship with some New World Iridoideae. The leaf margin type is similar to that of other Old World Iridoideae. Many leaf anatomical characters in Dietes are associated with xeromorphy. Leaf anatomy supports the division of Dietes into 2 subgenera.     

Leaf anatomy and phylogeny of Ixioideae (Iridaceae)

Leaf anatomy is described in Ixioideae, the largest subfamily of Iridaceae, with particular reference to phylogeny and systematics. Leaves in many genera have two rows of opposing vascular bundles (found also in many other Iridaceae), sometimes (except in e.g. Pillansia) combined with typical ixioid features such as a prominent pseudomidrib, mesophyll cells often elongated at right angles to the leaf axis, and epidermal cells also sometimes slightly laterally elongated, frequently with markedly sinuous anticlinal walls, and a single row of papillae per cell. Other characters are limited to a few genera. Anatomical characters are used together with data from other sources to construct a cladogram for the group. Although anatomical characters in general show much homoplasy, the relationships of the existing three tribes, Pillansieae, Watsonieae and Ixieae, diagnosed mainly on the basis of floral and inflorescence characters, are largely upheld by analysis, with at least two potentially useful subtribal groupings within Ixieae.     

Leaf anatomy and systematics of Homeriinae (Iridaceae)

Leaf anatomy is described in a range of species of the Old World subtribe Homeriinae, including species from all of the eight genera: Barnardiella, Galaxia, Gynandriris, Hexaglottis, Homeria, Moraea, Rheome and Roggeveldia. Homeriinae have bifacial leaves, otherwise unusual among Iridaceae, and an apomorphy for this group. Leaf anatomy also shows some unusual features, notably an 'extra' row of (inverted) vascular bundles in some specieS. A cladistic analysis using a broad range of data demonstrates that Moraea, the largest genus of the subtribe, is paraphyletic. The smaller genera are consistently clustered within Moraea. Subgenus Moraea is heterogeneous and requires redefinition. Although there are insufficient existing data for satisfactory resolution of the relationships of Homeriinae, information from leaf anatomy provides some useful indicators.     

Leaf anatomy of Ficus subsection Urostigma (Moraceae)

Species of Ficus subsection Urostigma show much overlapping variation in vegetative morphology, which often precludes correct identification of the species. The aim of this study was to describe the leaf anatomical characters and their variation and to check their suitability for identification. Included were 41 samples belonging to 25 species of subsection Urostigma, four samples belonging to two species of section Leucogyne and one specimen of Ficus glaberrima subsp. siamensis of subsection Conosycea. Transverse sections of lamina, midrib and petiole and cuticular macerations were used, and the observed anatomical characters are described for each species. On the basis of a limited number of studied samples, leaf anatomy shows little variation within each species and each species has a unique combination of character states, facilitating identification. Ficus arnottiana shows some leaf anatomical characters that are quite different from those of other members of subsection Urostigma, including a multiple epidermis and enlarged lithocysts on both sides of the leaf. Both characters are generally considered as typical for Ficus subsection Conosycea. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 259–281.     

Styloid crystals in Claoxylon (Euphorbiaceae) and allies (Claoxylinae) with notes on leaf anatomy

Claoxylon and Micrococca are the only Euphorbiaceae genera that have rough dried leaves (fresh ones are smooth) because of protruding styloid (needle-like) crystals more or less perpendicular to the leaf surface, which perforate the epidermis and cuticle. A broad leaf anatomical study of the subtribes Claoxylinae, the monogeneric Lobaniliinae, and Mercurialis of the Mercurialinae (95 of a possible 235 species in all six genera) showed that styloids are present in Claoxylon , Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca , and lacking in Claoxylopsis and Mercurialis . Contrary to Claoxylon , the dried leaves of Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca are not rough, because the styloids do not perforate the epidermis during drying and therefore herbarium leaves generally remain smooth. The presence of styloids supports a clade in a recent molecular phylogenetic study that unites subtribes Claoxylinae and Lobaniliinae as Claoxylinae s.l. Mercurialis (no styloids) is sister to all other taxa (with styloids) in the monophyletic Claoxylinae s.l. The styloids form a synapomorphy for a monophyletic part of the Claoxylinae ( Claoxylon , Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca ). Other leaf anatomical notes are provided, together with an overview of the occurrence of styloids, stomata, and druse crystals for most species in the Claoxylinae. The indumentum ranges from (virtually) absent to a sparse or dense tomentum of straight and thick- or thin-walled unicellular hairs (most common), curly hairs, or two-armed hairs ('Malpighiaceous hairs'). The last two hair types probably form diagnostic characters for species groups within the genus Claoxylon .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 445–457.     

Leaf damage effects on leaf expansion timing in Mallotus japonicus (Euphorbiaceae)

For many plant species, biotic factors determining the timing of leaf expansion have not been elucidated sufficiently. We investigated the effects of leaf damage on the timing of leaf defoliation and on the timing of leaf expansion in Mallotus japonicus (Euphorbiaceae). The degree of leaf herbivory of M. japonicus in the field was examined in summer, with subsequent investigation of the date of leaf defoliation in autumn and that of leaf expansion the following spring. Effects of artificial leaf damage on the timing of leaf defoliation and of leaf expansion were also examined in a greenhouse. In the field, the degree of leaf herbivory sustained by M. japonicus did not affect the timing of defoliation. However, the timing of leaf expansion the next spring advanced earlier, concomitantly with the increase of leaf damage during the previous year. Fifty per cent artificial leaf damage in M. japonicus saplings in summer had no marked effect on the timing of leaf defoliation in autumn. However, the effects of leaf damage on the timing of leaf expansion were apparent the following spring: the damaged plants expanded new leaves ca. 8 days earlier than control plants did. Plants that showed earlier leaf expansion tended to have a higher shoot/root ratio. Our results demonstrate that the plants advance the timing of their leaf expansion in response to leaf damage sustained during the previous year, suggesting that the shoot/root ratio is a determining factor.     

Leaf anatomy of Gluta (L.) Ding Hou (Anacardiaceae)

An anatomical study of the leaves of 21 species of Gluta (L.) Ding Hou (Anacardiaceae) reveals two major groups of species which reflect the original groups of Gluta L. and Melanorrhoea Wall., and a smaller group showing intermediate, or an admixture of, characters. The anatomical characters found to be of most use in this respect are: stomatal outline in surface view; stomatal density; glandular trichomes present/absent; glandular trichome body raised/sunken; cuticle striate/not striate; midrib dimensions as seen in transverse section; kind of simple trichomes (trichome-types 1–4); epidermal cell anticlinal wall undulation and whether visible or not on cuticular surface; resin ducts present/absent in medullary parenchyma of midrib. These characters have been used in a key to the species. Some evidence is given that the lacquer covering the leaf surface of some species is produced by the terminal cells of the glandular trichomes.     

Pollen morphology of the subtribe Cuspariinae (Rutaceae)

The neotropical subtribe Cuspariinae (Rutaceae) comprises as many as 26 genera and over 125 species. Pollen grains from 111 collections representing 71 species and 24 genera were examined by LM, SEM, and TEM. The pollen morphology of this subtribe is very diverse. Grains are mostly 3–6-aperturate and colporate, rarely porate (Spiranthera) or pantocolporate (Almeidea). Exine sculpturing is most commonly reticulate, sometimes perforate, foveolate-perforate, foveolate, foveolate-reticulate, reticulate, striate-reticulate, echinate, clavate, or baculate. The exine structure is columellate and tectate-perforate, columellate and semitectate, or intectate and is stratified into ektexine and endexine. The exine ofLeptothyrsa is distinctive in that the ektexine of the mesocolpium is longitudinally deeply ridged. The pollen ofHortia, characterized by a psilate exine with rare perforations, a very thick foot-layer, and reduced columellae, is unlike that of any member of the Cuspariinae and offers no support for the transfer of this genus from the Toddalioideae. The pollen data correlate with macromorphological characters and are taxonomically useful.     

Leaf anatomy of Greyia Hooker & Harvey (Greyiaceae)

The leaves of the three species, viz. Greyia sutherlandii Hooker & Harvey, G, radlkoferi Szyszyl. and G. flanaganii H. Bolus, of the endemic South African genus were studied morphologically and anatomically. Uniseriate branched hairs and uniseriate stalked glands occur on the leaves of G. radlkoferi and G. flanaganii. Mature leaves of G. sutherlandii usually have glands only, but hairs may occur, which are either an ecological adaptation or evidence of a transitional type between G. sutherlandii and G. radlkoferi. The leaves of Greyia are dorsiventral with anomocytic stomata. The latter occur in both leaf epidermides of G. sutherlandii but are rarely present in the adaxial leaf epidermis of G. radlkoferi and G. flanaganii. The uniseriate hypodermis of the lamina is interrupted beneath the stomata only and probably has a conducting function in Greyia , together with the tissues of the epidermis, the bundle sheaths and the bundle sheath extensions.