Systematic and comparative anatomy of Cymbidieae (Orchidaceae)

Cymbideae comprise an assemblage of 28 genera nearly all of which are represented in this study. Their anatomy is relatively homogenous with the exception of Govenia , in which roots lack velamen and pseudobulb vascular bundles lack sclerenchyma, conditions that do not obtain in other genera. Marginal fibre bundles in leaves of Grammatophyllum and Porphyroglottis consist of clusters of thicker-walled, narrower, epidermis-facing fibres as well as thinner-walled, wider, mesophyll-facing fibres. This feature also occurs in some species of Maxillaria . Baculate tilosomes appear in the roots of a majority of genera in Cymbidieae, as they do in species of Maxillaria , confirming DNA analyses showing a close relationship between tribes Cymbidieae and Maxillarieae. Govenia is singled out both on anatomical and molecular grounds as being ill-placed in Cymbidieae. Cladistic analysis produces only a few tentative hypotheses of phylogenetic relationships among the 28 genera, showing that anatomical characters are of limited value in assessing affinities within this tribe. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 1–27.     

Comparative vegetative anatomy and systematics of the angraecoids (Vandeae, Orchidaceae) with an emphasis on the leafless habit

The vegetative anatomy and morphology of 142 species of the angraecoid orchids (Angraecinae + Aerangidinae) and 18 species of Aeridinae were examined using light and scanning electron microscopy. Leafless members of Vandeae were of particular interest because of their unique growth habit. Leafy and leafless members of Angraecinae and Aerangidinae were examined and compared with specimens of Aeridinae. Vandeae were homogeneous in both leaf and root anatomy. A foliar hypodermis and fibre bundles were generally absent. Stegmata with spherical silica bodies were found associated with sclerenchyma and restricted to leaves in almost all specimens examined. Distinct inner tangential wall thickenings of the endovelamen occurred in several vandaceous genera. Exodermal proliferations and aeration units commonly occurred in both leafy and leafless Vandeae. Cladistic analyses of Angraecinae and Aerangidinae with members of Aeridinae and Polystachyinae as outgroups using 26 structural characters resulted in 20 000+ equally parsimonious trees. Vandeae formed the only well-supported clade in bootstrap analyses and were characterized by having a monopodial growth habit, spherical stegmata, loss of mucilage, and loss of tilosomes.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 165–218.     

Indeterminate leaves of Chisocheton (Meliaceae): survey of structure and development

Pinnately compound leaves in the Malesian genus Chisocheton (Meliaceae) have leaf-tip buds that continue to produce new pinnae (leaflets) periodically for many years. Juvenile leaves form a terminal pinna in place of the leaf-tip bud found in adult leaves. The histology of an old leaf-tip bud is similar to the entire leaf primordium in other species of Meliaceae with large pinnate leaves (e.g. Chukrasia and Dysoxylum ) which serve as examples of more typical leaves. Pinna initiation from this meristem continues after the first stage of leaf expansion as seen in the relatively constant number of pinna primordia in a large sampling of leaf-tip buds of varying ages. Structure and development are compared in leaves of nine species of Chisocheton , out of a total of approxiamtely 50 species in the genus. Species having small leaves (e.g. C. pentandrus ) show more branch-like, indeterminate leaf growth as compared with species with large leaves (e.g. C. macranthus ). The structure and development of leaves of Chisocheton are like the similar indeterminate leaves of the American and African genus Guarea . Some authors have used the indeterminate leaves of Chisocheton and Guarea as examples of intermediate organs showing 'fuzzy morphology' or 'partial homology.' Nevertheless, these unusual organs are considered here as being homologous with leaves of other Meliaceae based on their position, histology and ontogeny. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 207–221.     

Leaf epidermal micromorphology of Cercis (Fabaceae: Caesalpinioideae)

The micromorphology of leaf epidermal cells and stomata of all eight species and one form (11 samples) of Cercis were observed by scanning electron microscopy and light microscopy. Both the adaxial and abaxial epidermal cells are polygonal or irregular in shape; the anticlinal walls are straight and arched or undulate. Two types of stomata, which occur only on the abaxial surface of the leaves, are found in the genus. The atypical paracytic type is present in only one species, Cercis chingii, and the anomocytic type is present in all other species. Interspecific differences are minor in the genus with regard to leaf epidermal characters, except for C. chingii, which is characterized by atypical paracytic‐type stomata, a two‐lipped outer stomatal rim, the highest stomatal density and undulate and densely pitted anticlinal walls in the adaxial epidermis. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 539–547.     

Comparative vegetative anatomy and systematics of the Oncidiinae (Maxillarieae, Orchidaceae)

Subtribe Oncidiinae comprises a vegetatively heterogeneous assemblage of species that has persistently been incapable of organization. Anatomy was considered to be a possible means to resolve the perplexity of relationships amongst the constituent taxa. The consistent occurrence of a foliar hypodermis, homogeneous mesophyll, conical silica bodies in stegmata, and ubiquitous fibre bundles in leaves provides a matrix for linking the taxa, as do the parenchymatous pith and O-thickened endodermal cell walls in roots. However, the strict consensus of the 40 genera studied was completely unresolved, suggesting that vegetative characters alone are insufficient to assess the relationships amongst these taxa, a conclusion also reached for the remainder of Maxillarieae.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 91–107.     

Comparative vegetative anatomy and systematics of Spiranthoideae (Orchidaceae)

STERN, W. L., MORRIS, M. W., JUDD, W. S., PRIDGEON, A. M. & DRESSLER, R. L. 1993. Comparative vegetative anatomy and systematics of Spiranthoideae (Orchidaceae). The anatomy of leaf, stem and root of plants in the orchid subfamily Spiranthoideae was studied and described from the viewpoint of systematics. Plants were available from most of the geographic range. Tribes Diceratosteleae and Tropidieae show sinuous anticlinal epidermal cell walls in leaves, glandular foliar hairs, tetracytic para-mesoperigenous stomata, unitary tracheary components in the foliar midrib, foliar and cauline stegmata and sclerenchyma, typical cruciate starch grains, thick-walled exodermal, endodermal, and pericyclic cells, and conductive strands of the root embedded in sclerenchyma. The tribe Cranichideae shows straight to curvilinear anticlinal epidermal cell walls in leaves, lack glandular foliar hairs, have variably patterned mesoperigenous stomata, lack sclerenchyma throughout the parts studied, have a binary tracheary component in the foliar midrib, store starch in specialized amyloplasts (spiranthosomes), lack stegmata, have thin-walled exodermal, endodermal, and pericyclic cells, show scalariform thickenings in exodermal cells, and have conductive strands of the root embedded in parenchyma. In Cryptostylis the tracheary component of the foliar midrib is unitary, stomata lack subsidiary cells, starch grains are of the typical cruciate configuration, and passage cells of the endodermis are apparently associated with tilosomes. Anatomical data, when analysed cladistically, support the hypothesis that Spiranthoideae, as currently delimited, are polyphyletic. Corymborkis, Tropidia, and Diceratostele are more closely related to Palmorchis, a likely representative of a basal clade within subfamily Epidendroideae, than to genera of Cranichideae. Likewise, members of Cranichideae are more closely related to Diuris, a representative of subfamily Orchidoideae-tribe Diurideae, than to Corymborkis, Tropidia and Diceratostele. The Corymborkis– Tropidia-Diceratostele-bassd epidendroid [Palmorchis) clade may be diagnosed by the foliar synapomorphies of sinuous anticlinal walls of epidermal cells and presence of glandular hairs. The Cranichideae-orchidoid (Diuris) clade may be diagnosed by its variably patterned, mesoperigenous stomata, lack of vascular bundle sclerenchyma, absence of stegmata, unthickened endodermal cell walls in roots, and conductive cells of roots embedded in parenchyma. Relationships within this clade are quite unresolved, when only anatomical data are employed; however, all studied genera of Cranichideae, except Cryptostylis, possess a binary tracheary component in the foliar midrib. Cranichideae, excluding Cryptostylis, may be considered monophyletic. All Cranichideae, except Helaeria and Cryptostylis, possess spiranthosomes. Hetaeria may be a basal member within Cranichideae. We consider the phylogenetic position of Cryptostylis, in relation to Cranichideae vs. Diurideae, to be equivocal.     

西藏虎头兰和墨兰对强光的生理响应

兰属植物(Cymbidium)是重要的观赏花卉。该属大多数种类生长在适度荫蔽的环境中,但附生型的西藏虎头兰(C.tracyanum)却能在阳光直射的环境下良好生长。为了探究西藏虎头兰适应强光的生理机制,研究选取同属的地生型墨兰(C.sinense)与其进行对照实验,测定了这两种植物在不同光照强度下的叶绿素荧光参数和P700氧化还原态。结果表明,在强光下,西藏虎头兰光系统I和II活性的下降程度比墨兰小,而环式电子传递的激发程度更高。环式电子传递的激发有助于增强西藏虎头兰在强光下的光保护,而墨兰因环式电子激发程度较低,使其不能适应强光。由于附生环境更容易出现间歇性的直射光,西藏虎头兰的这种适应强光的能力可能有助于它更充分地利用附生环境中的光照资源。     

Systematic and comparative anatomy of Maxillarieae (Orchidaceae), sans Oncidiinae

On the basis of floral and vegetative morphology, 63 tropical American genera have been recognized within Maxillarieae. We were able to examine anatomical material of all subtribes, excluding Oncidiinae. Stegmata with conical silica bodies occur in leaves and stems of all subtribes excluding Ornithocephalinae, and pericyclic stegmata found in roots are characteristic of Lycastinae. Lycastinae and Maxillariinae are characterized by foliar glands, foliar fibre bundles and tilosomes. Endodermal cells are U-thickened in most Zygopetalinae; O-thickened in most Lycastinae, Ornithocephalinae and Telipogoninae; variously thickened in Maxillariinae; and thin-walled in Cryptarrhena lunata . Water-storage cells varied from thin-walled to variously banded throughout Maxillarieae. Cladistic analyses using anatomical characters yielded no resolution among subtribes, illustrating that anatomical characters are of limited value in assessing relationships within this tribe.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 251–274.     

Comparative anatomy and systematics of Catasetinae (Orchidaceae)

Catasetinae consist of five genera of pseudobulbous Orchidaceae of the Neotropics. Anatomy is characterized by sunken, three-celled foliar hairs, mostly tetracytic stomatal apparatuses, superficial stomata, homogeneous mesophyll, foliar fibre bundles, collateral vascular bundles in a single row, xylem and phloem sclerenchyma associated with vascular bundles in leaves, conical, and rough-surfaced silica bodies adjacent to vascular bundle sclerenchyma; epidermal cells of pseudobulbs with heavily thickened outer walls, pseudobulb ground tissue of assimilatory and water-storage cells, scattered vascular bundles in pseudobulbs, and sclerenchyma and stegmata associated only with phloem of pseudobulbs; roots with thin-walled velamen cells and tenuous spirals of cell wall material, distinctive epivelamen cells, thin-walled exodermal cells and vascular tissue embedded in parenchyma. Except for mucilaginous idioblasts that occur in Mormodes and Cycnoches , there are few outstanding anatomical differences among the five genera. Thus, there are few anatomical characteristics of phylogenetic value. The monophyly of Catasetinae is supported by the presence of sunken foliar hairs. Our results support a close relationship between Clowesia and Catasetum , and between Mormodes and Cycnoches. Among the outgroups Pteroglossaspis is especially distinctive.     

Ecological diversity and adaptive tendencies in the tropical fern Trichomanes L. (Hymenophyllaceae) with special reference to climbing and epiphytic habits

Among the basal fern families, the Hymenophyllaceae, with more than 600 species, display a high diversity in terms of their morphology and the habitats that they occupy. We have chosen to focus on Trichomanes L., a clearly defined genus for which a phylogeny is presently being developed, to investigate the appearance of the climbing and epiphytic habits, as well as the related supposed adaptive characters. In this study we present the first review of the different ecological types within the genus: terrestrial, climbing (divided into hemi-epiphytic forms and true lianas), and epiphytic types. The study of several features concerning stem morphology and leaf size allows a proposal on relationships between ecology and plant morphology. Terrestrial species display a thick monocaulous rhizome with robust roots and short internodes. Climbing species are characterized by a branched, thick, creeping rhizome with long internodes. Epiphytic species also exhibit long, creeping and branching stems with long internodes but the rhizome is fine to filiform. Under these circumstances, there is a reduction of root system and frond size leading to dwarfism in numerous instances. This may be related to an extreme hygrophilous epiphytic strategy. Finally, hypotheses on the evolution of these habits and hence on the evolutionary relationships between ecology and characters are presented and discussed.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 41–63.     

Comparative vegetative anatomy and systematics of Vanilla (Orchidaceae)

Vanilla is a pantropical genus of green-stemmed vines bearing clasping (aerial) and absorbing (terrestrial) roots. Most vanillas bear normal, thick foliage leaves; others produce fugacious bracts. Seventeen species, including both types were studied. Foliage leaves of Vanilla are glabrous, have abaxial, tetracytic stomatal apparatuses, and a homogeneous mesophyll. Species may or may not have a uniseriate hypodermis. Crystals occur in the foliar epidermises of some species, but all species have crystalliferous idioblasts with raphides in the mesophyll. Vascular bundles in leaves are collateral and occur in a single series alternating large and small. Sclerenchyma may or may not be associated with the vascular bundles. Scale leaves may be crescent or C-shaped and usually have abaxial stomatal apparatuses. A hypodermis may or may not be present; the mesophyll contains raphide bundles in idioblasts. Vascular bundles are collateral and occur in a single row sometimes aligned close to the adaxial surface. They may or may not be associated with sclerenchyma. Stems of leafy vanillas show a sclerenchyma band separating cortex from ground tissue; stems of leafless vanillas do not show a sclerenchyma band. Ground tissue of the stem may consist solely of assimilatory cells or mixed assimilatory and water-storage cells. In some species centrally located assimilatory cells are surrounded by layers of water-storage cells. A uniseriate hypodermis is present in all stems. Sclerenchyma may completely surround the scattered collateral vascular bundles, occur only on the phloem side, or be absent. Both aerial and terrestrial roots are notable for their uniseriate velamen the cell walls of which may be unmarked or ornamented with anticlinal strips. Exodermis is uniseriate; the cells vary from barely thickened to strongly thickened. Only the outer and radial walls are thickened. Cortical cells of aerial roots generally have chloroplasts that are lacking from the same tissue of terrestrial roots. Raphide bundles occur in thin-walled cortical idioblasts. Endodermis and pericycle are uniseriate; pericycle cells are all ?-thickened opposite the phloem. Cells of the endodermis are either ?- or ∪-thickened opposite the phloem. Vascular tissue may be embedded in thin- or thick-walled sclerenchyma or in parenchyma. Metaxylem cells are always wider in terrestrial than in aerial roots of the same species. Pith cells are generally parenchymatous but sclerotic in a few species.     

Stegmata in Orchidales: character state distribution and polarity

The- distribution of stegmata in Orchidales is given for 130 species representing 105 genera. The stegmata occur in leaves and stems as longitudinal files of silica cells. lining fibre bundles or vascular bundle sheaths. The silica bodies contained in orchid stegmata arc of two major kinds, spherical and conical. The species investigated are characterized either by a single kind of silica body or by lack of silica cells. Absence of stegmata and presence of stegmata with conical bodies are the two most common character states in the order. The stegmata containing spherical bodies characterize Vandeae and Eriinae, Podochilinae, and Dendrobiinae within Epidendreae
Comparison of character slates of the various groups within the family is used for a discussion of evolutionary polarity. The function of silica accumulation is reconsidered in the light of the epiphytic life-form of many of the investigated orchids.     

Vegetative anatomy and systematics of Triphorinae (Orchidaceae)

Triphorinae represents a group of three anatomically simple genera, the structural features of which are unspecialized. The anomocytic stomatal pattern occurs in all genera; it predominates in Triphora. A foliar hypodermis, sclerenchyma, fibre bundles and stegmata are absent. The mesophyll is homogeneous. The exodermal and endodermal cells in the roots are entirely thin‐walled and tilosomes are absent. However, there are anatomical modifications that appear to be unique: root hairs in Monophyllorchis are borne on velamenal buttresses and, in Psilochilus, they arise endogenously. In the root vascular system of Psilochilus, the metaxylem occurs as a circumferential band. The surfaces of stems in Triphora are tuberculate. Mycorrhizae appear to characterize the root cortices of all genera. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 203–210.     

Litter‐trapping plants: filter‐feeders of the plant kingdom

Litter‐trapping plants have specialized growth habits and morphologies that enable them to capture falling leaf litter and other debris, which the plants use for nutrition after the litter has decayed. Litter is trapped via rosettes of leaves, specially modified leaves and/or upward‐growing roots (so‐called ‘root baskets’). Litter‐trappers, both epiphytic and terrestrial, are found throughout the tropics, with only a few extra‐tropical species, and they have evolved in many plant families. The trapped litter mass is a source of nutrients for litter‐trapping plants, as well as food and housing for commensal organisms. Despite their unique mode of life, litter‐trapping plants are not well documented, and many questions remain about their distribution, physiology and evolution.–© 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 554–586.     

Fruit and seed ontogeny related to the seed behaviour of two tropical species of Caesalpinia (Leguminosae)

Caesalpinia echinata and C. ferrea var. ferrea have different seed behaviours and seed and fruit types. Comparison of the seed ontogeny and anatomy partly explained the differences in seed behaviour between these two species of Brazilian legumes; some differences were also related to fruit development. The seed coat in C. ferrea consisted of two layers of osteosclereids, as well as macrosclereids and fibres, to form a typical legume seed coat, whereas C. echinata had only macrosclereids and fibres. In C. echinata , the developing seed coat had paracytic stomata, a feature rarely found in legume seeds. These seed coat features may account for the low longevity of C. echinata seeds. The embryogeny was similar in both species, with no differences in the relationship between embryo growth and seed growth. The seeds of both species behaved as typical endospermic seeds, despite their different morphological classification (exendospermic orthodox seeds were described for C. echinata and endospermic orthodox seeds for C. ferrea ). Embryo growth in C. ferrea accelerated when the sclerenchyma of the pericarp was developing, whereas embryonic growth in C. echinata was associated with the conclusion of spine and secretory reservoir development in the pericarp. Other features observed included an endothelial layer that secreted mucilage in both species, a nucellar summit, which grew up into the micropyle, and a placental obturator that connected the ovarian tissue to the ovule in C. ferrea . © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 57–70.     

Comparative morphology of the leaf epidermis in Schisandra (Schisandraceae)

The leaf epidermis of 127 samples representing ten species within Schisandra Michaux. and one species of the related genus, Kadsura Kaempf. ex Juss., was investigated using light and scanning electron microscopy. Many characters of the leaf epidermis in Schisandra , such as pattern of epidermal cells, type of stomata, shape of guard cell pairs and cuticular ornamentation, are usually constant within species and thus make good characters for studying the relationship between and within genera. A new character, rim number, of the outer stomatal rim in the genus is introduced. It is shown that double outer stomatal rims occur only in evergreen Schisandra species, whereas a single rim occurs in deciduous species. This character supports the classification of Schisandra into two subgenera based on habit and androecial organs. This classification is also supported by additional morphological and molecular taxonomic characters. Kadsura coccinea (Lem.) Smith A. C. is the most primitive taxon in the related genus Kadsura . The outer stomatal rim of this species also has double rims. Combined with morphological and molecular evidence, this suggests that Schisandra and Kadsura are closely related and may share a recent common ancestor.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 39–56.     

A peculiar new Orthotrichum species (Orthotrichaceae, Bryopsida) from central Argentina

A new epiphytic Orthotrichum species ( Orthotrichum spiculatum F. Lara, Garilleti & Mazimpaka sp. nov. ) is described from the sierra of Córdoba (Argentina). The new species has most of the characteristics of subgenus Pulchella (Schimp.) Vitt, but it is unique because of having eight exostome teeth pairs and 16 broad, strongly papillose endostome segments. Additionally, its upper leaves have green, acuminate, dentate–spiculate apices.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 477–482.     

Natural selection and the distribution of shell colour morphs in three species of Littoraria (Gastropoda: Littorinidae) in Moreton Bay, Queensland

The distribution of yellow, brown and red morphs of sympatric species of Littoraria were recorded on mangrove trees of the genus Avicennia within Moreton Bay, Queensland. The roles of background mimicry (leaf vs. bark, dark vs. light), niche selection and thermal tolerance (sunny vs. shaded positions and height above ground) were examined. The yellow advantage found previously in the area was tested. Total yellow morph frequency adjusted to a reduction in leaf background on pruned trees. Morph frequencies in Littoraria species reflect differences in habitat use. L. filosa (high yellow frequency) was more frequently found on leaves at the highest tree levels, while L. luteola (high brown frequency) was more frequently found on branches at lower levels. It is therefore argued that morphs mimic background elements. Previously reported niche selection by yellow and brown morphs of leaf and bark backgrounds is shown to be a result of the distribution of L. luteola on branches and L. filosa on leaves. At warmer times of the year, yellow L. filosa were more common in sunny positions; this is thought to be a result of thermal tolerance. There appears to be some advantage to particular morphs on particular tree types, but this relationship needs to be examined further. Mangrove-dwelling Littoraria are a promising model to investigate molluscan polymorphism. In the past, erroneous identification of sympatric species may have influenced the accuracy of reported patterns. We used allozyme electrophoretic markers as a precise identification technique. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 219–232.