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.     

Leaf morphology of hosts and nonhosts of the thrips Heliothrips haemorrhoidalis (Bouché)

This study highlights the morphological differences between two groups of plants; those that are recorded as hosts of the thrips Heliothrips haemorrhoidalis (Bouché) and those that remain free from infestation. Scanning electron microscope techniques were used to describe the morphology of the leaf surface of 19 species in order to help identify which morphological features could play a role in the selection of plant species by thrips from among a diverse botanical collection. H. haemorrhoidalis had a preference for species with leaves that were coriaceous, with one or both surfaces being smooth. Plants evading these thrips commonly possessed glandular trichomes. Thus morphology may have a role in deterring thrips from the leaf surface, as well as influencing the behaviour of predators that control thrips. Further detailed studies into the chemistry of leaves of hosts and nonhost species may help to further our understanding of selection mechanisms.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 109–130.     

Comparative and functional leaf anatomy of selected Alstroemeriaceae of mainly Chilean origin

The resupinate leaves of 16 species of Alstroemeriaceae were examined using light- and scanning electron microscopy. The leaf anatomy is described for all of the species, that of the petiole and stem for selected species. The mesophyll consists of chlorenchyma and includes idioblasts that contain raphides. Dorsiventral, isolateral or isobilateral leaf types were observed. Petioles are always isolateral. Two epidermal types are commonly observed: type I contains jigsaw puzzle-like intercostal cells and longitudinally elongated cells above the veins; type II contains only longitudinally elongated cells, usually longer, above the veins. Some species have an epidermis which differs from the main types. All species show adaptation to resupination by having an inverted anatomy. Due to the twist of the leaves, adaxial indicates the lower surface and abaxial the upper. Stomata are found on both surfaces. Palisade cells, when they occur, are always on the abaxial surface. Most species are mesomorphic in spite of the dry environments in which they grow; a few show xeromorphic features. The leaves are compared and discussed with relation to ecological conditions.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 261−272.     

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.     

The genus Borassus (Arecaceae) in West Africa, with a description of a new species from Burkina Faso

Borassus akeassii Bayton, Ouédraogo & Guinko sp. nov. (Arecaceae) is described as a new species from western Burkina Faso in West Africa. It has been confused with the widely distributed African species B. aethiopum and more recently with the Asian B. flabellifer . However, it is distinguished by its glaucous, green leaves with weakly armed petioles and a characteristic pattern of lamina venation. The fruits have a pointed apex and are greenish when ripe, and the flowers of the pistillate inflorescence are arranged in three spirals. The pollen has a reticulate tectum and distinctive ornamentation. The distribution of B. akeassii is discussed and the status of the varieties of Borassus aethiopum (var. bagamojensis and var. senegalensis ) is examined.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 419–427.     

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.     

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.     

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.     

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.     

A microhistological survey on the trees of a relict subtropical laurel forest from the Macaronesian Islands as a base for assessing vertebrate plant diet

A microhistological collection and its respective key on the leaves and fleshy fruits produced by the mostly endemic trees that integrate the relict laurel forest in the Macaronesian Islands are presented. Epidermal tissues from the adaxial and abaxial surfaces of leaves and fruits of 23 species were extracted by scraping and prepared on individual microscope slides. An optical microscope with a camera lucida fixed at magnifications of ×400 was used to analyse and to draw the morphological traits of epidermal tissues to the same scale. Furthermore, quantitative data for those congeneric species were also obtained by using an image analysis program system. The results indicate that this microhistological method permits the differentiation of practically all species of trees present in the Macaronesian laurel forest. Furthermore, most species belonging to the same taxa (genus or family) show a general common pattern in the morphology of the different epidermal traits. Lastly, despite the effort that constitutes the preparation of plant microhistological collections of a determined ecosystem, it is of basic importance because it makes possible the performance of feeding ecological studies of several herbivorous and frugivorous vertebrate species. These results provide crucial information that elucidates the functioning of the food web and energetic flux dynamics of the Macaronesian laurel forest ecosystem.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 409–426.     

A new dwarf Coffea (Rubiaceae) from southern Cameroon

A distinctive new species of dwarf monocaulous Coffea (Rubiaceae) from Cameroon is described and illustrated. Coffea mapiana is the second dwarf monocaulous known from Cameroon. Its diagnostic characters are elucidated and its taxonomic affinities are discussed; a conservation assessment is provided.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 425–430.     

Floral ontogeny, petal diversity and nectary uniformity in Bruniaceae

Bruniaceae are a small family subendemic to the Cape Floristic Region. Flowers are actinomorphic, choripetalous, pentamerous and tetracyclic. The petals show diverse adaxial swellings, which have been quoted as an example of diplophylly. Developmental studies confirm the true choripetaly of the flowers, thus pointing to an affinity to the Apiales within the euasterids II. They reject, however, the hypothesis of diplophylly as the petal swellings grow out rather late and are not vascularized. According to the position, size and shape of the swellings, six petal types are distinguished, which in part have phylogenetic information. Nectaries occur on the upper part of the ovary. Nectar is exuded through modified stomata serving as secretory channels. All genera have gynoecial nectaries of the mesenchymatous type.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 459–477.     

Notes on some new records and new species of cetrarioid lichens from India

Additional occurrences of cetrarioid lichens in India are documented. Tuckneraria sikkimensis Divakar & Upreti sp. nov. is described as a new species. Tuckneraria ahtii Randlane & Saag, T. togashii (Asahina) Randlane & A. Thell and Cetrelia sinensis W.L. Culb. & C.F. Culb. are reported as new records.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 249–251.     

New chromosome counts in the genus Cousinia (Asteraceae) from Iran

Chromosome counts are reported of 38 populations representing 24 species of the genus Cousinia from Iran, one of the main centres of speciation of the genus. Sixteen of the counts are new to science. Our results confirm that Cousinia exhibits a complex dysploid series ranging from x  = 13 to x  = 9. One of the basic chromosome numbers, x  = 9, is new for the genus and must be confirmed. Some considerations on the correlation between chromosome numbers and section classification are made.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 411–419.     

A distinctive new species of Viola (Violaceae) from Yunnan, China

A new species of Viola (Violaceae) from north-western Yunnan, China, is described and illustrated. Viola dimorphophylla Y. S. Chen & Q. E. Yang sp. nov. is endemic to Zhongdian County, north-western Yunnan, and is very easily distinguishable from all other Chinese species of the genus by having obviously dimorphic leaves, with the basal ones being long petiolate, undivided and widely cordate, and the cauline ones sessile, linear and verticillate.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 115–119.     

A new Mantalania species (Rubiaceae) from Madagascar

Mantalania longipedunculata De Block & A.P. Davis, a new species of Rubiaceae (Gardenieae) from Île Sainte Marie, Madagascar, is described, illustrated, and compared with the three other species in the genus. An extinction risk assessment is given, using the categories and criteria of the World Conservation Union (IUCN).  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 421–424.     

A new species of Estinnophyton from the Lower Devonian Posongchong Formation, Yunnan, China; its phylogenetic and palaeophytogeographical significance

A new species of early vascular land plant, Estinnophyton yunnanense , is described from the Lower Devonian (upper Pragian) Posongchong Formation at Zhichang village, Gumu Town, Wenshan District, Yunnan Province, China. This plant possesses aerial stems with isotomous branching. The leaves are slender, once- or twice-bifurcated, and arranged in low spirals or pseudowhorls. Fertile leaves are morphologically identical to the vegetative ones, clustered on the axis, forming a loose strobilus-like structure. There are three to six fertile leaves in each gyre. Two ovoid-elongate sporangia are singly attached to the adaxial surface each subtended by a recurved stalk, either at the base of each segment in a once-bifurcate fertile leaf or below the points of successive divisions in a twice-bifurcate fertile leaf. Estinnophyton yunnanense differs from two other species described previously from Europe, E .  gracile and E .  wahnbachense , mainly in possessing two single stalked sporangia on each fertile leaf rather than two pairs of sporangia, as well as in the dimensions of its leaves. In view of the complex taxonomy and nomenclature surrounding the type material of Estinnophyton , we considered possible emendation of the generic diagnosis based on the new Chinese material. Following comparison with typical members of the Protolepidodendrales and other taxa, Estinnophyton is considered to have had a closer affinity with primitive sphenopsids than the protolepidodendralean lycopsids. A comparison between Chinese and European floras containing Estinnophyton indicates that South China and Western Europe had floristic elements in common although they were in different phytogeographical units during the Early Devonian epoch.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 201–216.