Anatomy of the Dicotyledons.
About: This article is published in American Midland Naturalist.The article was published on 1950-11-01. It has received 2511 citations till now.
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TL;DR: Wood anatomy of Griselinia littoralis and Corokla is described, which are diffuse-porous woods which have mainly heterogeneous type II Rays and rhom-boidal crystals are present in the ray parenchyma.
Abstract: Wood anatomy of Griselinia littoralis Raoul, G. lucida Forst. f., Corokla cotoneaster Raoul, C. buddleioides A. Cunn., and C. macrocarpa Kirk is described. These woods are diffuse-porous. The vessels are angular and have exclusively scalariform perforation plates with 7 to 31 bars. In Corokla, very fine spiral thickening is sometimes present in vessels and fibrous tissue. Axial parenchyma which is particularly sparse in Corokla is diffuse, diffusc-in-aggregatcs, and scanty paratracheal. Rays are mainly heterogeneous type II. In Griselinia rhom-boidal crystals are present in the ray parenchyma. Vessels pits to rays are fully bordered in Corokla, while in Griselinia these are part-bordered or without borders. The fibrous tissue which is sometimes septate, is mainly composed of fibre-tracheids. Anatomical differences between species are described. The confusion in the literature regarding the occurrence and the arrangement of axial parenchyma in Griselinia and Corokla is clarified.
101 citations
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02 Jun 2008TL;DR: This paper used fossil plants to study the K-T boundary and evaluated scenarios for the K -T boundary event and the Floral effects of the K T boundary event in North America.
Abstract: Preface Part I. Background: 1. Introduction 2. Resolution of the K-T boundary 3. Using fossil plants to study the K-T boundary 4. Brief history of K-T boundary paleobotany and palynology 5. Overview of latest Cretaceous and early Paleocene vegetation Part II. Regional Case Studies: 6. Williston Basin - the most complete K-T sections known 7. Other North American records 8. Eurasia 9. Remnants of Gondwana Part III. Interpretations: 10. Assessment of the K-T boundary event 11. Evaluation of scenarios for the K-T event 12. Floral effects of the K-T boundary event References Index.
101 citations
TL;DR: In this paper, morphometric analyses show quantitative differences in anatomical characters of wood and charcoal between wild and cultivated olive, showing that growth ring width and number of vessels per group are both significant criteria for discriminating between wild-and cultivated olive.
100 citations
TL;DR: It is proposed that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species' degree of folivory.
Abstract: Background
Primates—including fossil species of apes and hominins—show variation in their degree of molar enamel thickness, a trait long thought to reflect a diet of hard or tough foods. The early hominins demonstrated molar enamel thickness of moderate to extreme degrees, which suggested to most researchers that they ate hard foods obtained on or near the ground, such as nuts, seeds, tubers, and roots. We propose an alternative hypothesis—that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species' degree of folivory.
Methodology/Principal Findings
From a combination of dietary data and evidence for the levels of phytoliths in plant families in the literature, we calculated the percentage of plant foods rich in phytoliths in the diets of twelve extant primates with wide variation in their molar enamel thickness. Additional dietary data from the literature provided the percentage of each primate's diet made up of plants and of leaves. A statistical analysis of these variables showed that the amount of abrasive silica phytoliths in the diets of our sample primates correlated positively with the thickness of their molar enamel, constrained by the amount of leaves in their diet (R2 = 0.875; p<.0006).
Conclusions/Significance
The need to resist abrasion from phytoliths appears to be a key selective force behind the evolution of thick molar enamel in primates. The extreme molar enamel thickness of the teeth of the East African hominin Paranthropus boisei, long thought to suggest a diet comprising predominantly hard objects, instead appears to indicate a diet with plants high in abrasive silica phytoliths.
100 citations
TL;DR: Generating a more detailed understanding of the structural and compositional modifications associated with the transition from plastic to elastic collenchyma cell wall properties is likely to provide significant insights into how specific configurations of cell wall polymers result in specific functional properties.
100 citations