Leaf and stem anatomy of Vochysiaceae in relation to subfamilial and suprafamilial systematics

Several leaf anatomical features are potentially systematically informative within both the family Vochysiaceae and the order Myrtales, notably tracheoidal idioblasts, mucilage cells and secretory canals. Tracheoids with spiral wall thickenings are present in the mesophyll of most species of Vochysia , and also occur in several other families of Myrtales. Mucilage cells are common in the leaf epidermis in some Vochysiaceae. Secretory ducts are present in the midrib in Salvertia and Vochysia , which are apparently closely related, although Salvertia also shares some leaf anatomical characters with Qualea and Callisthene . Anatomical data do not support the segregation of Ruizterania from Qualea ; leaves of R. albiflora leaves are very similar to those of Q. paraensis in venation pattern, and leaf and stem anatomy. Different venation patterns are characteristic of sections within the genus Qualea , but within the large genus Vochysia , leaf anatomy is variable even within a subsection. Amongst other Myrtales, leaf anatomy of Vochysiaceae most closely resembles that of Combretaceae and Onagraceae. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 339–364.     

Functional leaf anatomy of Bomarea Mirb. (Alstroemeriaceae)

The leaf anatomy of Bomarea is described and related to ecological conditions. The principal architecture of all species is very similar; adaptations are developed in numerous differences, for instance degree of lignification. All species have inverse leaves, the adaxial side being the stomatous side. In most species, the leaves are resupinate, the lower surface being the adaxial. Theories for the cause of resupination are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 73–90.     

Leaf anatomy of Bruniaceae: ecological, systematic and phylogenetic aspects

CARLQUIST, S., 1991. Leaf anatomy of Bruniaceae: ecological, systematic and phylogenetic aspects. Quantitative and qualitative data are given for 60 species of the 12 genera of Bruniaceae; most data are based on liquid-preserved material. Leaves of Bruniaceae are basically linear (broader forms are probably derived) with an apicula that contains phellogen activity. Most bruniaceous leaves have some degree of isolateral construction, with transition to normal bifacial construction in a few species, but more commonly transition to 'inverse' bifacial structure (stomata on adaxial face, palisade on abaxial face). The latter type is correlated with the tendency for leaves to be appressed to stems. Tannins and very likely other dark-staining materials are very characteristic of mesophyll cells. Six genera have a large strand of fibres on the midvein and rhomboidal crystals in bundle sheath cells. The other six genera have few or no fibres on veins and have druses in mesophyll cells (but not in bundle sheath cells). These distinctions may relate to intrafamilial taxonomy, but they also support the primitive position usually accorded to Audouinia, Thamnea and Tittmannia. A key to genera based on leaf antomy is offered. Details of epidermal cell shape, cuticular relief and trichome form and structure based on scanning electron microscopy are given. Leaf anatomy, combined with other features, favours a relationship between Bruniaceae and Grubbiaceae in particular and in broader contexts allies Bruniaceae to rosalean and possibly hamamelidalean families.     

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.     

Leaf anatomy and the occurrence of false veins in Asplenium (Aspleniaceae, Pteridophyta)

False veins in African afro-alpine (2000–4700 m) Asplenium species with long creeping rhizomes and highly dissected leaves are morphologically and anatomically similar to true veins but differ in the absence of a vascular bundle. False veins in Aspleniaceae may have originated by the fusion of leaf lobes, and are more similar to those in Angiopteris and Thelypteris than to those in Davallia and Hymenophyllaceae. Because false veins are long and extend from the leaf margin to the junction of the neighbouring true veins in A. actiniopteroides , A. goetzei , A. majus , A. praegracile , A . sp. nov. and A. uhligii , but short, not reaching this junction in A. decompositum , A. demerkense , A. kassneri , A. linckii and A. mildbraedii , and even absent in A. aethiopicum , A. lademannianum , A. simii , A. stipicellatum and A. volkensii , they can be used for identification in this enigmatic group of ferns.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 187–194.     

Two new species of Lessingianthus (Vernonieae, Asteraceae) from the Brazilian highlands

Two additional species of Lessingianthus , L. bakerianus and L. lanuginosus , from the campo cerrado vegetation of central Brazil, are described and illustrated. The first species is characterized by the presence of capitula arranged in groups, nine to 12 florets per head, leaves sessile, oblong to ovate leaf blades with the lower surface densely lanate, sparsely villous on the main veins. It has certain resemblance to L. syncephalus (Sch. Bip. ex Baker) H. Rob. and L. brevipetiolatus (Sch. Bip. ex Baker) H. Rob., which present petiolate leaves and leaf blades lanceolate, cuneate or attenuate at the base. L. lanuginosus is superficially similar to L. buddleiifolius (Mart. ex DC.) H. Rob., but differs in having smooth stems, woolly indumentum, smaller heads and the largest leaves disposed at the middle of the stem.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 150 , 487–493.     

Anatomical structure and distribution of secondary metabolites as a peripheral defence strategy in Aloe hereroensis leaves

Eight leaves from four different plants of Aloe hereroensis and 18 leaf parts of each leaf were tested by anatomic, fluorescence microscopy and TLC methods. Four phenolic secondary metabolites, homonataloin and three isomers of aloeresin, were found in the leaves. The highest content of these metabolites was found in the top third of a leaf and along the leaf margins. In the margins, the content of the four secondary metabolites in the adaxial was higher than in the abaxial direction. In the centre parts of the leaves, the metabolic content of the abaxial parts was higher than in the adaxial parts. The results indicate that homonataloin mainly accumulates in the inner bundle sheath cells (IBSC). The three isomers of aloeresin appear in the outer bundle sheath and in the boundary cells between the chlorenchyma and water-storage tissues. The density of the vascular bundles, the area ratio of the chlorenchyma to the tested counterpart, and the area ratio of the IBSC to a whole bundle are important structural factors to determine the differences in the content of these four secondary metabolites in all the leaf parts. The distribution according to the rosette leaf arrangement and the existence of the 'cocktail' of four phenolic secondary metabolites indicate a peripheral defence strategy of this plant. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 107–116.     

To which genus of Asteraceae does Liabum oblanceolatum belong? Vegetative characters have the answer

The West Indian species Liabum oblanceolatum Urb. & Ekman was established on the basis of sterile young specimens represented by acaulescent herbs with rosulate leaves. However, these specimens have important traits that do not correspond to Liabum Adans. More than 90 genera of Asteraceae occur in Hispaniola (= Santo Domingo), but only 14 of them include species represented by acaulescent herbs with rosulate or grouped leaves at the base of the stem. From these genera, Chaptalia Vent. and Liabum are the most similar to the types of L. oblanceolatum . Habit, leaf arrangement, lamina shape, leaf margin, leaf surface, leaf margin intrasection, leaf venation, leaf pubescence, leaf trichomes, stomata and upper surface leaf cuticle were analysed in the type specimens of L. oblanceolatum and in species of Chaptalia and Liabum of Hispaniola. The vegetative trichomes are described in detail. The analysis reveals that the type specimens of L. oblanceolatum fit with all the vegetative traits of Chaptalia angustata Urb. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 479–486.     

Amana kuocangshanica (Liliaceae), a new species from south-east China

Amana kuocangshanica D. Y. Tan & D. Y. Hong is described as a new species from Mt. Kuocang, Zhejiang Province, south-east China. Morphological observations and a statistical analysis of the new species and its relatives show that it is most closely related to A. anhuiensis and A. erythronioides , but differs in having the lower leaf oblanceolate, the widest at two-thirds length from the base, tunics glabrous inside, and fruit beaks 5–7.5 mm long. The morphologies of the pollen, seeds, and epidermal cells of the leaves of this new species are described.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 435–442.     

Epidermal structures and stomatal parameters of Chinese endemic Glyptostrobus pensilis (Taxodiaceae)

Glyptostrobus pensilis K. Koch, the only living species, is endemic to southern China. Epidermal structures of G .  pensilis have been studied on leaves collected from Guangzhou, southern China, the native locality of the species, and from Hangzhou, eastern China, the cultivated locality. Leaves are linear, linear-subulate and scale-like. Epidermal cells are rectangular and elongate parallel to the mid-vein on areas lacking stomata, and short, with rounded corners, on intrastomatal areas. Stomatal bands lie parallel to the mid-vein on both surfaces of leaves. Commonly the stomata have five or six subsidiary cells. Stomatal parameters (density and index) of the same surfaces of linear leaves from Guangzhou and Hangzhou show no statistically significant differences ( P  > 0.05). Considering the stomatal parameters of the same surfaces of linear-subulate leaves between the two localities, the stomatal index of the abaxial surfaces reveals no significant differences ( P  > 0.05), while the stomatal index of the adaxial surfaces and the stomatal density of both surfaces exhibit significant differences ( P  < 0.05). Intra-individual variation in stomatal index is smaller than that in stomatal density based on the coefficient of variability of stomatal parameters of the same areas of leaves. When studying the correlation between stomatal parameters of G. pensilis and atmospheric CO₂ concentrations, the stomatal parameters of linear leaves are mostly significant, and stomatal index is more useful than stomatal density.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 153–162.     

Shoot and compound leaf comparisons in eudicots: dynamic morphology as an alternative approach

Recent developmental studies suggest that the compound leaf is a more or less incompletely developed shoot. Instead of treating compound leaves and shoots as non-homologous, this interpretation draws a continuum between them. The present work considers the plant as a hierarchical series of units on which similar developmental processes are at work, and where each level (shoot, compound leaf, leaflet) is 'repeated' by the next higher level. Measurements related to the expression of developmental processes operating on leaves at the shoot level and on leaflets at the compound leaf level were used to determine if similar processes are at work at these different levels during early stages of organogenesis. Plants with compound leaves showing acropetal leaflet inception, representing a total of 16 species from ten eudicot families, were studied. Based on several types of quantitative analyses, there appears to be a continuum between so-called shoots, compound leaves and leaflets in the species studied. This perspective, qualified as dynamic morphology, both parallels and complements the classical interpretation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 219−230.     

Leaf teeth in certain Salicaceae and 'Flacourtiaceae'

The leaf teeth glands in four taxa from Salicaceae and six from 'Flacourtiaceae' were examined using both light and scanning electron microscopes. There appears to be a progression from glands of simple structure in the flacourtiaceous taxa and a tendency to a more complicated development in morphology and anatomy of the salicaceous species.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 241–256.     

Comparative floral anatomy of Pontederiaceae

Floral anatomy is described in eight species (representing five genera) of Pontederiaceae, and floral ontogeny is described in Pontederia cordata. The results are assessed in the context of recent phylogenetic work on Pontederiaceae, which indicates that the unilocular ovary condition has been achieved by two different, non-homologous routes in Pontederiaceae: via loss of interlocular septa in Heteranthera and Hydrothrix , and via pseudomonomery in Pontederia , which has a single fertile carpel. Absence of septal nectaries has evolved more than once in Pontederiaceae, at least in Heterantha and Monochoria , probably due to a transfer of the insect reward from nectar to pollen in these taxa. The presence of an elliptical or linear unvascularized appendage on the abaxial outer stamen in Monochoria is also probably correlated with enantiostyly. In Pontederia , air spaces in the ovary wall are modified into canals, each with a ring of apparently secretory epithelial cells.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 395–408.     

Morphology and morphogenesis of ensiform leaves, syndesmy of shoots and an understanding of the thalloid plant body in species of Apinagia, Mourera and Marathrum (Podostemaceae)

The flattened, irregularly shaped and lobed or dissected leaves of Apinagia riedelii , A. latifolia , A. goejei , Mourera aspera and Marathrum utile (subfamily Podostemoideae) are ensiform in structure. After the typical bifacial inception, further growth of leaves proceeds in the midrib area, i.e. in the median plane of the leaf. The lower leaf zone is characterized by a sheath that orientates 'at the side of the blade', i.e. at the adaxial edge of the sword-like leaf. The ensiform blades are lobed, incised or pinnately dissected with the tips terminated in elongated threads or thin filaments. Leaves of Apinagia riedelii resemble pinnately dissected compound leaves. The dissected structure represents a secondary superimposition of the ensiform shape and a parallel development to compound leaves. It is interpreted as an adaptation to the rapid current, established in the floating shoots of these aquatic plants. The basal portions of main shoots and successive branches are fused due to a retarded separation. Fusion of this kind has been termed a syndesmy. The fused region of shoots is superseded by the fusion of the lower leaf zones of (distichously positioned) adjacent leaves, occurring at their margins. The fused leaf bases form a cavity for the terminal flower bud of each shoot and cover it in the form of a hood. The flower buds are hidden from external view. The meristematic growing zones are thus protected and enclosed within the syndesmic plant body which, in this way, attains the 'thalloid' appearance especially developed in Apinagia goejei and A. latifolia but also present in the other species. The results of this study enable an understanding of the particular appearance of these Podostemoideae as modifications of the typical structures according to the 'principle of variable proportions'.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 47–71.     

A new species of Arctotis (Compositae, Arctotideae) from kommetjie grassland in Eastern Cape Province, South Africa

Arctotis debensis R.J.McKenzie, a new species from the Albany Centre of Floristic Endemism, South Africa, is described and illustrated. It grows almost exclusively in grassland on kommetjies, a distinctive landform of depressions and mounds associated with giant earthworms, in a restricted area west of King William's Town, Eastern Cape Province. It is the first plant taxon reported to be endemic or near-endemic to this unusual habitat. The new species appears to have been collected rarely and previous collections examined have remained undetermined to species level. The new species is distinguished from closely allied species by the combination of its usually larger dimensions in all parts, prostrate habit, coriaceous leaves that are green, scabrous, and eglandular on the adaxial surface and densely lanate on the abaxial surface, and involucral-bract morphology.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 581–588.     

Consistent and variable leaf anatomical characters in Carex (Cyperaceae)

The anatomy and morphology of leaves in Carex have the potential to be taxonomically useful. However, studies on the variability of leaf characteristics in the genus are sparse. Researchers therefore risk using leaf anatomical characters without the knowledge of whether they are consistent in a species. We examined 22 qualitative and seven quantitative leaf anatomy characters from transverse leaf sections to test their consistency across 11 Carex spp. The characters were clearly described and primarily microscopic. Some characters were found to exhibit high levels of intraspecific variation, whereas other characters exhibited high levels of consistency in a species, including the shape of the leaf section, the density of papillae and the size of epidermal cells. Caution must be applied when choosing leaf anatomy to delimit taxa because of the intraspecific variability found in some characters, but sufficient numbers of invariant characters exist to provide useful taxonomic separation. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 371–384.