Ecology And Growth Habit Of Laveineopteris: A Gymnosperm from the Late Carboniferous Tropical Rain Forests

Cyclopterid leaves were borne on the same Late Carboniferous medullosalean plants that bore the pinnate fronds currently known as Laveineopteris . They were morphologically and anatomically different from the pinnate foliage, and presumably were also physiologically different. The cyclopterids are here interpreted as having been shade leaves and the pinnate foliage sun leaves. The juvenile Laveineopteris plant probably consisted of a monopole sapling bearing only cyclopterid leaves, which optimized growth in canopy shade conditions. On reaching the canopy level, the plant produced a crown of pinnate sun leaves. Cyclopterids were also borne epiphyllously in the proximal parts of the pinnate fronds; this may have represented a transitional light–level between canopy and subcanopy conditions. Thus, in this reconstruction, the cyclopterid leaves were complementary to the pinnate foliage of the adult Laveineopteris plant, and played a key role in its growth habit and ecology.     

Stratigraphic occurrences and vegetational patterns of Pennsylvanian pteridosperms in Euramerican coal swamps

The vegetation of many Euramerican coal swamps is known from coal-ball peats in the tropical rainy zone across the paleocontinent of Laurussia in the Upper Carboniferous. The stratigraphic occurrences of coal balls in Europe (lower Westphalian) and in North America (upper Westphalian and lower Stephanian) are largely complementary and a revised correlation chart is given. Quantitative analyses of the vegetation from these autochthonous peats are combined with coal palynology to determine on overview of swamp vegetation patterns during the Westphalian and early Stephanian. In comparison to the dominance and great diversity of pteridosperms in the Upper Carboniferous compression floras, seed ferns were minor to subdominant elements in the coal-ball peats. The quantitative composition of organ assemblages of the principal pteridosperms is given with stratigraphic occurrences of Medullosa and Sutcliffia (Medullosaceae), Heterangium, Lyginopteris, Microspermopteris, and Schopfiastrum (Lyginopteridaceaea) and Callistophyton (Callistophytaceae). The major peat contributors among pteridosperms are Lyginopteris (?90%) in the Westphalian A and Medullosa (?95%) in the Westphalian D and Stephanian. Lyginopteris became extinct in the early Westphalian B and Medullosa became abundant during the Westphalian C–D transition and a subdominant in the Stephanian contributing 13–21% of the permineralized peats. Paleoecological interpretations indicate that medullosan trees were most abundant but patchy in distribution in drier swamp stages with enriched nutrients and near major channels in swamps during the Westphalian D. It is suggested that the swamp pteridosperms are probably quite similar to or identical with some of the representatives in the more diverse compression floras. The evolution and diversity noted in swamp pteridosperms are considered principally the product of adjacent lowland communities which repeatedly introduced seeds into the wetlands. The swamp pteridosperms exhibit the greatest fluctuation in abundance (biomass) from site to site in the same coal, probably the highest level of diversity and the only steady pattern of increase in importance during the Late Carboniferous with the possible exception of the Westphalian B–C interval. The close relationships inferred between swamp pteridosperms and their lowland seed sources are also compatible with the frequent association of tree ferns and seed ferns during the Westphalian D and in the Stephanian when these two kinds of frond-bearing trees formed most of the vegetation in both lowland and swamp environments.     

Korallipteris,a new genus for Mesozoic Gleichenia-like fern fronds

A new morphogenus, Korallipteris, is proposed to accommodate fertile or sterile fern fronds possessing essentially Gleichenia-like morphology (e.g., pinnate fronds with small pecopteroid pinnules) but lacking diagnostic features that allow their classification at fern family-level. The aim is thus, to solve an old nomenclatural problem that involves the use of illegitimate genera, such as Gleichenites Goeppert and Microphyllopteris Arber. Several species of Gleichenites described from the Mesozoic of Argentina and Chile, and Microphyllopteris unisora Cantrill and Nagalingum from Antarctica are here reassigned to Korallipteris gen. nov. The proposal of Nagalingum and Cantrill to preserve Gleicheniaceaephyllum Crabtree emend. Nagalingum and Cantrill for true Gleicheniaceous ferns, diagnosed by having an arrested laminar bud, is here accepted.     

Two new late Carboniferous Neuropteris species (Medullosales) from Saarland, Germany and their palaeobiogeographical significance

Two new species ( Neuropteris terminiscus and N. kneuperi ) are described from the Bolsovian ('Westphalian C') of Saarland. N. terminiscus had previously been misidentified as Paripteris pseudograndinioides , but the pinnae are clearly imparipinnate and thus cannot belong to that morphogenus. N. kneuperi had previously been misidentified as Neuropteris obliqua and N. heterophylla , both which appear to be absent from Saar-Lorraine. This is considered further evidence of the distinctive nature of the Westphalian vegetation of the Saar-Lorraine Basin, especially among the seed-plants.  © 2002 The Linnean Society of London , Botanical Journal of the Linnean Society , 2002, 139 , 193–205.     

Old fronds serve as a vernal carbon source in the wintergreen fern Dryopteris intermedia (Aspleniaceae)

Maintaining green leaves beyond the growing season has been hypothesized to benefit plants by supplying either a nutrient or a carbon source. Understanding such ecophysiological aspects of plants will help us to appreciate how a species functions in its environment and predict how it might be affected by future changes in that environment. The wintergreen fern species Dryopteris intermedia does not retranslocate nitrogen and phosphorus from old fronds in spring, but photosynthesis does take place in the old fronds during this season. To determine if carbon fixed in the old fronds is translocated to other parts of the plant, we labeled old fronds with (13)C via photosynthetic uptake and examined old fronds, new fronds, fine roots, and rhizomes for (13)C content 1 day and 1 month after labeling the old fronds. Vernally fixed carbon was translocated to the new fronds but not significantly to the below ground tissues. Old fronds in this species, therefore, serve as a carbon source for vernal growth of new fronds. This is the first study in which a fern was labeled with (13)C to track vernally fixed carbon from old fronds to the rest of the plant in a wintergreen species. Future research should examine the precise timing of this carbon movement and examine other species for a similar or contrasting strategy.     

Two species of Selaginella cones and their spores from the Bohemian Carboniferous continental basins of the Czech Republic

Two species of Selaginella cones from the Bohemian Upper Carboniferous continental basins of the Bolsovian and Westphalian D age are described, together with their in situ spores. Two specimens of Selaginella gutbierii yielded microspores closely comparable with the dispersed species Cirratriradites saturnii and megaspores closely comparable with the dispersed species Triangulatisporites vermiculatus. Microspores closely comparable with the dispersed species Cirratriradites annulatus and megaspores resemble the dispersed species Triangulatisporites tertius were isolated from cones of Selaginella cf. leptostachys. All the spores isolated from one cone are of the same type and would be referred to one dispersed micro- and megaspore species if found as Sporae dispersae. The paper contains a review of all palynologically studied Carboniferous Selaginella and Selaginella-like cones and reviews of all in situ and dispersed Cirratriradites and Triangulatisporites spores.     

中国大羽羊齿植物分叉蕨叶的首次发现--兼论亚洲与北美大羽羊齿植物之异同

东亚与北美大羽羊齿植物间的主要差异在于蕨叶的结构：北美大羽羊齿植物的蕨叶为单叶或二歧分叉叶,而东亚的大羽羊齿植物以往只知为羽状复叶或不分叉的单叶,因之,二歧分叉蕨叶在中国的发现具有十分重要的意义,它使东亚与北美大羽羊齿植物之间的关系变得更为密切,虽然其间仍存在不实质性的差异,同时,对东亚和北美华夏羊齿Cathaysiopteris之间的异同作了较详的讨论。     

Twin shoots borne on a Botryopteris frond from the British upper carboniferous

A long rachis of Bottyopteris aff. hirsuta bearing twin opposite lateral shoots is described from a coal ball of Westphalian age collected in Lancashire. The simultaneous emission, in the middle region of a frond, of two short axes each bearing a large number of poorly developed leaves is a feature hitherto unrecorded for the genus. The specimen suggests that this Paleozoic fern consisted of long fronds whose branching pattern showed a certain capacity for morphological variation; it provides yet another example of the surprisingly limited development of shoots borne on Botryopteris fronds.     

Pennsylvanian miospore assemblages from the Bèdero Section,Varese, Italian Southern Alps

Thin continental Carboniferous sequences crop out sparsely in the western Southern Alps (Alpe Logone, Mesenzana, Grantola, Bosco Valtravaglia-Fabiasco, Val Tresa, etc.) and are currently the subject of a detailed litho- and biostratigraphic revision, to reconsider their chronological position with respect to previously published age constraints. The age of these Upper Palaeozoic sedimentary successions, scattered over a wide area and strongly tectonized along major structural lineaments, has long been debated between Westphalian and Stephanian. The present work focuses mainly on the palynology of the Brezzo di Bèdero section (Luino, Lake Maggiore). The recovered palynoflora is assigned to 42 spore genera and 76 species of which one genus and 10 species are newly proposed. Fifty-seven spore species and 19 pollen species are described and illustrated. Qualitatively, the Bèdero palynoflora shows strong affinities to those of Western Europe. The most abundant palynomorphs are trilete spores known to be characteristics of the late Westphalian and early Stephanian assemblages. These are characterized by the remarkable presence of Florinites and subordinately Wilsonites species, low numbers of Potonieisporites, rare Limitisporites and Vesicaspora, and very rare Latensina-Cordaitina pollen. The occurrence of diverse monolete spores Laevigatosporites, Punctatosporites, Spinosporites, Thymospora and Torispora, with common Lundbladispora gigantea, L. simonii, Stenozonotriletes rubius n. sp. together with the absence of plicate and taeniate pollen grains suggests a strong resemblance to the late Westphalian–early Stephanian interval assigned to the OT Zone of Western Europe. Variations in the quantitative composition can be likely attributed to variations in the environmental setting with regards to non-forming peat deposits. The palynological suite is indicative of the existence of a well-established lowland Cordaiteans vegetation and well settled pterophytic, pteridosperm and subordinately sphenophytic and lycophytic, hygrophytic plant communities.     

LYCOSPORA FROM CARBONIFEROUS LEPIDOSTROBUS COMPRESSIONS

Spores were extracted from Carboniferous Lepidostrobus compressions in order to associate in situ microspores with dispersed species of Lycospora. Two hundred twenty-six cones were examined, of which 61 contained spores. Fertile cones came from the Westphalian D of England, Namurian B through Westphalian D of the Appalachian and Illinois basins, and the Westphalian D of the Western Interior. Cones were separated into species based on microspore and cone morphology. Lycospora trigonoreticulata was produced by Lepidostrobus princeps from Westphalian C-D rocks from Missouri, the Illinois Basin, and the Appalachian Basin. Lycospora rotunda was produced by Lepidostrobus sp. A from Westphalian A rocks of Alabama. Two cone species produced Lycospora torquifer: Lepidostrobus praelongus from the Westphalian D of Pennsylvania and Lepidostrobus variabilis from the Westphalian A and C of the Illinois and Appalachian basins. Lycospora punctata was produced by Lepidostrobus cf. squarrosus from the Westphalian D of England, the Appalachian Basin, and Illinois Basin. Lycospora noctuina was produced by Lepidostrobus haslingdenensis from the Namurian B/C of Illinois. Microspore species are differentiated primarily on the basis of size, cingulum structure and width, and ornamentation. Cone species differ in width and distal lamina size, shape, and attitude. Lycospora species isolated from clastic species of Lepidostrobus differ completely from those of coal-swamp species, confirming that lycopod trees from clastic environments represent biologically different species from those centered in coal swamps.     

Ashicaulis woolfei n. sp.: additional evidence for the antiquity of osmundaceous ferns from the Triassic of Antarctica

Numerous small fern trunks and dispersed osmundaceous frond fragments occur within a Middle Triassic silicified peat near Fremouw Peak in the Transantarctic Mountains of Antarctica. These specimens form the basis of a new species of osmundaceous ferns that further helps to characterize the early Mesozoic vegetation of high latitude Gondwana. Ashicaulis woolfei n. sp. consists of small, upright trunks with a persistent armor of frond bases, adventitious roots, and vegetative frond parts. In cross section the trunks are ～2.5 cm in diameter and include up to 45 frond bases. Stems range from 5 to 8 mm in diameter with a xylem cylinder of 8-9 xylem segments separated by leaf gaps. Phyllotaxy is variable, approaching 2/5 or 3/8, with 10-12 frond traces in the cortex. Stipes have parenchymatous, stipular wings that are usually devoid of sclerenchyma; fronds are pinnate with alternate-subopposite pinnatifid pinnules. Although the absence of fertile pinnules and sporangia precludes assigning the fossils to a living genus, this species demonstrates that ferns with stelar architecture and histology similar to Osmunda subgenus Osmundastrum (Osmundaceae) were present in the Southern Hemisphere by the mid-Triassic.     

The Middle Jurassic flora from Stonesfield, Oxfordshire, UK

The Stonesfield 'Slate' of Oxfordshire has yielded a diverse Middle Jurassic flora, containing 25 morphospecies, dominated by remains of araucariacean and cheirolepidiacean conifers, bennettitaleans, and leaves of the possible gymnosperm Pelourdea . It mainly represents coastal vegetation, which included mangrove-like stands of Ptilophyllum , and conifers probably growing in lowland coastal habitats that were subjected to periodic water-stress. The Pelourdea leaves may have drifted in from drier, more upland habitats. The flora is similar, but not identical to, the slightly older floras from the Cotswold 'Slate' of Gloucestershire, such as from Eyeford and Sevenhampton. Also comparable are the contemporaneous floras preserved in marine deposits in France and the Venetian Alps of Italy. It is quite different from the Middle Jurassic flora of Yorkshire, which is thought to represent vegetation growing in deltaic habitats. The new combinations Ptilophyllum pectiniformis (Sternberg), Komlopteris speciosa (Ettingshausen) and Pachypteris macrophylla (Brongniart) are proposed for species found at Stonesfield. Nilssoniopteris solitarium (Phillips) comb. nov. is proposed for the species previously named Nilssoniopteris vittata (Brongniart). Taeniopteris vittata Brongniart is retained as the type species of Taeniopteris , a morphogenus to be used for entire cycadophyte leaves that cannot be definitely assigned to the cycads or bennettitaleans. Conites is shown to be an earlier nomenclatural synonym of Bucklandia , to be used for casts and compressions of cycadophyte stems. This requires a number of new combinations for species that have hitherto been included in Bucklandia : Conites anomala (Stokes and Webb), C. gigas (Seward), C. indica (Seward), C. milleriana (Carruthers), C. pustulosa (Harris) and C. yatesii (Carruthers).     

A new rhynchonelliform brachiopod Longtancunella with soft-part preservation from the Hongjingshao Formation (Cambrian Stage 3) in Yunnan,South China

Rhynchonelliform brachiopods made their first appearance in early Cambrian, and became a major group within the palaeozoic evolutionary fauna since late Cambrian. Exceptionally preserved fossils from the early Cambrian Lagerstätten provide valuable chances to investigate their phylogeny and ecology. Longtancunella is one of the most interesting early rhynchonelliforms, and has been mainly recovered from the Chengjiang Lagerstätte (Series 2, Stage 3). Here, we report a new rhynchonelliform Longtancunella xiazhuangensis n. sp. from the lower Hongjingshao Formation (upper Stage 3) in Yunnan Province, China. These specimens were well preserved with soft parts, including pinnate mantle canal system and a pedicle. It is identified as a new species based mainly on its difference in shell ornamentations, pinnate mantle canals and pedicle morphology from the type species. Its pedicle looks unusually stout with distinct annulated lamellae on the surface, and reveals crucial evidence in illustrating its ecology and settling strategy as an early marine epifauna. The ecological interaction between L. xiazhuangensis and other marine animals also provides insights into the food web structure in the early Cambrian.     

A SHORT-TERM DEMOGRAPHIC STUDY OF CYSTOSEIRA OSMUNDACEA (FUCALES: CYSTOSEIRACEAE) IN CENTRAL CALIFORNIA1

Several demographic features were examined in the field over a period of eleven months for the subtidal alga Cystoseira osmundacea (Turner) C. Agardh at two localities near Monterey, California. This species showed a restricted distribution with depth, with peak average numbers of 3–4 plants per m² occurring at 6–8 m and forming a dense canopy on the surface of the sea. Below 10 m depth, there was a decline in the abundance of plants and also in the proportion of plants which bore seasonal fronds and reproductive tissue. Macrocystis pyrifera (L.) C. Agardh plants were also common at both localities. There was a negative correlation between the presence of this species and C. osmundacea at a scale of 1 m², but no correlation at 4, 9, and 25 m². Cohorts of C. osmundacea were mapped and tagged at one locality. The plants had markedly seasonal growth, with the greatest elongation of fronds occurring between March and June. Dense surface canopies and reproductive tissue were present during the summer months of June–August. These seasonal fronds were shed during September, leaving small perennial holdfasts and fronds. Plants were strictly dioecious, and there was a one-to-one ratio of male to female plants at both localities. Length-dry weight relationships showed that the largest plants had over 80% of their weight invested in seasonal fronds (vegetative plus reproductive tissue). Recruits of C. osmundacea at one locality appeared during September–November only in areas cleared to bare substratum. There was 15% survival of recruits between November and the following May, while 98% of the original mapped cohort survived for the 11 months of the study.     

Localization and Dynamic Change of Saponin in Vegetative Organs of Polygala tenuifolia

Anatomical, histochemical and phytochemical methods were used to investigate the structure, localization and dynamic changes of total saponin and senegenin of vegetative organs in Polygala tenuifolia Willd. Histochemical localization results showed that saponin accumulated mainly in parenchyma cells of vegetative organs. The phytochemical results also showed that the saponin accumulated in the vegetative organs of P. tenuifolia, with higher content in roots and lower content in the aerial parts that included stems and leaves. The saponin content and dry weight of the vegetative organs of P. tenuifolia had dynamic variance at the developmental stages and all reached the highest level in the post-fruit period. Hence, the roots and aerial parts should be gathered in August to make full use of the plant. As the root is the main medicinal organ of P. tenuifolia, the content of total saponin and senegenin of different aged and different parts of the root were determined. The content of total saponin and senegenin exhibited a sustained decreasing trend with increasing root age; therefore, theannual roots had high quality. The content of total saponin and senegenin in different parts of the root showed obvious variation. The content in the "skin areas" was much higher than that of xylem. The results offer a theoretical basis for determining the appropriate harvesting stage and a reasonable harvest of P. tenuifolia.     

Molecular phylogeny of Chinese Rubia (Rubiaceae: Rubieae) inferred from nuclear and plastid DNA sequences

Rubia L. is the type genus of the coffee family Rubiaceae and the third largest genus in the tribe Rubieae, comprising ca. 80 species restricted to the Old World. China is an important diversity center for Rubia, where approximately half of its species occur. However, its internal phylogenetic relationships are still poorly understood. The objective of the present study is to contribute to the phylogenetic relationships within Rubia, using the nuclear internal transcribed spacer and six plastid markers and focusing on species from China. Twenty-seven species of Rubia were sampled to infer their phylogeny using Maximum parsimony, Maximum likelihood, and Bayesian analyses. The monophyly of Rubia is supported, provided that R. rezniczenkoana Litv. is excluded from Rubia and transferred to Galium as a new combination: G. rezniczenkoanum (Litv.) L. E Yang & Z. L. Nie. Within Rubia, two clades are clearly supported. They correspond to the traditional sect. Rubias.l. (A) and sect. Oligoneura Pojark. (B), and are morphologically mainly separable by their pinnate (A) versus palmate (B) leaf venation. Plesiomorphic features are the pinnate leaf veining in sect. Rubia s.l. and the occurrence of some species with opposite leaves and true stipules in sect. Oligoneura. In sect. Oligoneura one can assume an evolution from species with opposite leaves and true stipules (as in the R. siamensis Craib group) to those with whorls of two leaves and two leaf-like stipules (as in ser. Chinenses and the R. mandersii Collett & Hemsl. group) and finally with whorls of 6 or even more elements (as in ser. Cordifoliae). The correlation between clades recognized by DNA analyses and available differential morphological features is partly only loose, particularly in the group of R. cordifolia with 2×, 4×, and 6× cytotypes. This may be due to rapid evolutionary divergence and/or hybridization and allopolyploidy.     

Plant microfossil analysis of coprolites of the critically endangered kakapo (Strigops habroptilus) parrot from New Zealand

We present here the results of the analysis of pollen, spores, starch and other microscopic plant material in 52 coprolites of the critically endangered kakapo (Strigops habroptilus), a New Zealand endemic parrot. The six sampling sites (caves, rock overhangs) are in widely separate geographic regions in the South Island, across an altitudinal range encompassing lowland, montane and sub-alpine environments. Radiometric testing gives average ages of discrete coprolite groups ranging from modern to 2514 ± 43 ¹⁴C yr BP (Wk-19164). A wide variety of plant taxa is identified in the coprolites, comprising cones, flowers, leaves and fronds of ~ 30 podocarps, dicotyledonous trees, shrubs and lianas, grasses, ferns, lycopods, mosses and liverworts. This supports previous observations that kakapo are versatile feeders, using a broad spectrum of foods that may only be available for short periods and intermittent years. Many of the food taxa we identify are consistent with the studies of modern kakapo diet. We also identify several new foods, potentially of value in developing food supplements to increase breeding frequency of the current kakapo population. The most commonly identified plant parts in coprolites were fern fronds (monoletes, Hymenophyllum, Cyathea smithii), followed by podocarp cones and leaves. Lack of starch in the coprolites suggests that the lycopod and fern rhizomes reported in modern kakapo diet were not commonly eaten. The data provide initial botanical evidence of diet from coprolites of an extant bird.     

基于人工培养的浮萍快速无性繁殖营养条件研究

为探究并优化浮萍人工培养技术, 研究以广布种紫萍(Spirodela polyrrhiza)和青萍(Lemna minor)为主要研究对象, 探索两种浮萍植物在不同营养水平的Hoagland和Hunter培养液中的鲜重、叶状体数的生长变化状况。结果表明: (1)紫萍和青萍鲜重在Hoagland培养液的不同营养水平下先增加后减少, 而在Hunter营养液中呈持续增长趋势; 两种浮萍的鲜重最大相对增长率(RGR)分别为0.11和0.18, 鲜重受浮萍品种和培养基类型及其不同营养水平影响显著(P<0.05), 以青萍在Hunter原液培养基下的无性繁殖产生的生物量最高。(2)紫萍和青萍叶状体数在Hoagland培养液的不同营养水平下先增加后减少, 而同鲜重一样在Hunter营养液中呈不断增长趋势; 两种浮萍的叶状体最大相对增长率分别为0.14和0.19, 叶状体生长的RGR变化同样受浮萍品种和培养基类型及营养水平影响显著(P<0.05), 以青萍在Hunter原液的营养环境下收获的叶状体数最高。(3)两种浮萍在Hoagland和Hunter营养液的不同营养水平下鲜重/叶状体比呈下降趋势, 表明两种浮萍在适应不同营养时优先繁殖子代叶状体, 以扩大种的适合度。研究认为Hunter原液可作为广布种青萍的最优培养条件, 可实现短时间内收获较大浮萍鲜生物量和叶状体数, 为进一步资源化利用提供原材料。     

Bracken thiaminase-mediated neurotoxic syndromes

The toxicity of bracken ( Pteridium aquilinum (L.) Kuhn) to animals is complicated because this plant elaborates more than one type of agent harmful to livestock. An enzyme, thiaminase I, which destroys thiamine, is responsible for the neurotoxic syndrome. Using a radiochemical assay, the distribution of thiaminase I activity in bracken throughout the growing season has been ascertained: levels are high in the rhizome and young buds, but fall sharply in the fronds as the aerial parts of the plant unfold.
The so-called thermostable 'antithiamine' factors present in bracken and other plant species are discussed.
The biochemical lesions of thiamine deficiency in animals are briefly outlined, and the clinical syndrome caused by the inclusion of bracken fronds or rhizomes in the diet for simple-stomached animals (rat, horse, pig) and a ruminant (sheep) are described.
All these neurotoxic syndromes respond to thiamine therapy in a dramatic way, if administered during the early stages of the disease.     

Nystroemiaceae,a new family of Permian gymnosperms from China with an unusual combination of features

Nystroemiaceae is proposed as a new family of gymnosperms from the Permian of Cathaysia that adds to the diversity of gymnosperms known from this critical time in seed plant evolution. This family is characterized by bifurcating and highly branched pinnate ovuliferous organs bearing bicornute ovules (seeds) and entire leaves with anastomozing veins that are born on complex and modern-looking branching systems with clear axillary branching. The reconstruction is based on numerous large specimens from two localities in North China, in which the different plant parts are attached to each other. The ovulate structures show some apparently plesiomorphic (primitive) character states more typical of early seed plants, whereas the leaves and branches show the clearly apomorphic (derived) character states of broad-leaved gymnosperms.