The Role of Self-Incompatibility and Sexual Selection in the Gymnosperm-Angiosperm Transition: A Hypothesis

This is the publisher's version, also available electronically from www.jstor.org.No abstract is available for this item

The significance of human induced and natural erosion features (lavakas) on the central highlands of Madagascar

Massive hill slope erosion in Madagascar is represented by the widespread gullies called ‘lavaka’. Lavakas may be result of natural processes that involves a combination of continuous tectonic uplift that maintains a high angle of repose, ground water sapping at the soil - saprolite interface, and subsequent collapse of the soil surface due to low grade seismic activity in the central highlands. Forest cover ranges between 25-45% in the study area and is primarily restricted to riparian and lavaka habitats. Development of forest cover associated with riparian and lavaka habitats may be due to increased soil moisture, exposure of a less nutrient poor saprolite and/or soil compaction. In addition, riparian and lavaka habitats harbor a significantly higher diversity of plant species than the surrounding grasslands. Lavakas may be a result of natural processes and may play a role in the development of Madagascar’s landscape evolution.RÉSUMÉLes formes d’érosion connues sous le terme de lavakas peuvent être le résultat d’un processus naturel impliquant à la fois un soulèvement tectonique continu qui maintient un angle de repos important, un processus de sape des eaux souterraines à l’interface sol–saprolite et un effondrement consécutif de la surface du sol du à la faible activité sismique des hautes terres du centre. Ce phénomène est suivi d’une succession géomorphologique à long terme et d’une succession de végétation liées aux lavakas, de sorte que les lavakas et la végétation qu’ils abritent sont isolés du bassin versant principal. Les rivières et les bassins versants en tant qu’éléments séparateurs ont, semble-t-il, joué un rôle dans la richesse de la biodiversité de Madagascar. La présente étude montre que la végétation associée aux forêts riveraines et aux lavakas représente 25-45% de la couverture forestière des hautes terres du centre. L’absence de forêts sur les zones herbeuses voisines ou la présence d’une succession de végétation liée aux zones herbeuses suggère que le développement de la végétation arborée pourrait être lié à des changements du degré d’humidité du sol, de la disponibilité des éléments nutritifs ou du tassement du sol. Le taux d’humidité s’est avéré être constant dans tous les habitats échantillonnés. La disponibilité en éléments nutritifs peut jouer un rôle dans la structure de la végétation. Les lavakas se formant par l’effondrement du sol superficiel par un processus de sape des eaux souterraines à l‘interface sol–saprolite, la zone racinaire de la végétation se trouve alors à proximité des saprolites pauvres en éléments nutritifs. Le degré de tassement du sol diffère de manière significative entre les forêts ripicoles/lavakas et les zones herbeuses. Les zones herbeuses ont montré des mesures de résistance du sol au pénétromètre élevées (moyenne de 17,9) et un profil de tassement qui peut limiter le développement racinaire d’un certain nombre d’espèces. Les mesures effectuées dans les forêts riveraines et les lavakas étaient respectivement de 14,0 et 9,7 qui sont des valeurs compatibles avec un développement racinaire. De ce fait, les différences entre les structures de la végétation et la diversité peuvent trouver leur origine dans la capacité des plantes à développer leur système racinaire. Il existe également un rapport inverse entre la diversité spécifique et le degré de tassement du sol dans les trois habitats. La mobilité des sols dans les lavakas et les habitats ripicoles peut réduire le tassement en surface et juste en dessous en favorisant ainsi un labourage naturel. Les lavakas peuvent ainsi être le résultat d’un processus naturel et jouer un rôle important dans le développement de l’évolution des paysages de Madagascar et de la biodiversité

EQ-5D in Central and Eastern Europe : 2000-2015

Objective: Cost per quality-adjusted life year data are required for reimbursement decisions in many Central and Eastern European (CEE) countries. EQ-5D is by far the most commonly used instrument to generate utility values in CEE. This study aims to systematically review the literature on EQ-5D from eight CEE countries. Methods: An electronic database search was performed up to July 1, 2015 to identify original EQ-5D studies from the countries of interest. We analysed the use of EQ-5D with respect to clinical areas, methodological rigor, population norms and value sets. Results: We identified 143 studies providing 152 country-specific results with a total sample size of 81,619: Austria (n=11), Bulgaria (n=6), Czech Republic (n=18), Hungary (n=47), Poland (n=51), Romania (n=2), Slovakia (n=3) and Slovenia (n=14). Cardiovascular (20%), neurologic (16%), musculoskeletal (15%) and endocrine/nutritional/metabolic diseases (14%) were the most frequently studied clinical areas. Overall 112 (78%) of the studies reported EQ VAS results and 86 (60%) EQ-5D index scores, of which 27 (31%) did not specify the applied tariff. Hungary, Poland and Slovenia have population norms. Poland and Slovenia also have a national value set. Conclusions: Increasing use of EQ-5D is observed throughout CEE. The spread of health technology assessment activities in countries seems to be reflected in the number of EQ-5D studies. However, improvement in informed use and methodological quality of reporting is needed. In jurisdictions where no national value set is available, in order to ensure comparability we recommend to apply the most frequently used UK tariff. Regional collaboration between CEE countries should be strengthened

The ultrastructure of Upper Palaeozoic and Mesozoic pollen from southern Africa and Asia

The dispersed pollen taxa Cycadopites, Monosulcites, Bennetitteaepollenites, Pityosporites, and Inaperturopollenites recovered from Permian to Jurassic sediments in southern Africa and Asia were examined ultrastructurally. Cycadopites, Monosulcites, Bennetitteaepollenites and Inaperturopollenites wall structure is characterized by homogeneous outer layer that is variously lacunate, and is underlain by a lamellated basal layer. Only one species of Monosulcites recovered from Jurassic sediments of Afghanistan showed a well-developed tectum, an infrastructural layer composed of columellae, or irregularly shaped columellae underlain by a basal layer. The saccate pollen of Pityosporites has an infrastructural layer of irregularly shaped anastomosing rods, the sacci are formed by an expansion of infrastructural layer in the region of the saccus (i.e. protosaccate sensu Scheuring). A majority of Permian, Triassic and Jurassic saccate and non-saccate monosulcate pollen is characterized by limited morphological diversity with regard to sculpturing and wall structure type compared to the diversity in angiosperm monosulcate pollen; however, there are pre-Cretaceous monosulcate pollen types that exhibit angiospermous pollen characteristics.Palaeo-anthropology Scientific Trus

Angiosperm Origins and Evolution Based on Dispersed Fossil Pollen Ultrastructure

Volume: 71Start Page: 444End Page: 46

A Mexican Curandera in Arizona

Desert Plants is published by The University of Arizona for the Boyce Thompson Southwestern Arboretum. For more information about this unique botanical journal, please email the College of Agriculture and Life Sciences Publications Office at [email protected]

Comparative Pollen Morphology of Brachylena, Tarchananthus and Two Species of Tubulifloridites (Asteraceae) From the Eocene, Knysna Lignite of South Africa

Two fossil taxa Tubulifloridites antipodica and T. viteauensis recovered from the Eocene Knysna Lignite of South Africa were examined with scanning (SEM) and transmission electron microscopy (TEM). The details of their sculpturing and wall structure are similar to the same species of fossil dispersed pollen taxa recovered from southwestern Africa and South America. Fifteen species of the woody South African taxa, Brachylaena (9 species) and Tarchonanthus (6 species) were investigated with SEM and TEM. All of the taxa are tricolporate, spherical to slightly prolate, microechinate to echinate and have a bilayered columellate infrastructure, except B. ilicifolia, which has a single columellate infrastructural level with the granularization of the outer portion of the infrastructural layer or the inner layer of the tectum. There is a similar distribution of plesiomorphic and derived pollen characters in a number of aster subfamilies and tribes suggesting a similar evolutionary progression of pollen, and pollen wall character evolution was occurring synchronously in a variety of aster subfamilies during the middle Tertiary and that these unique pollen features may be important to the evolution and diversification of the Asteraceae

Comparative Pollen Morphology and Its Relationship to Phylogeny of Pollen in the Hamamelidae

Volume: 73Start Page: 348End Page: 38

Characterization and Ecological Significance of a Seed Bank From the Upper Pennsylvanian Wise Formation, Southwest Virginia

Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed longevity, which reduces the effect of environmental variability on seed germination and development. The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts. The estimated seed density of 192 seeds/m2 in the Palaeozoic seed bank falls within the range of modern seed banks, but at the lower end of modern seed bank densities in a variety of habitats