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: In this paper, the faunal and botanical data from the first millennium bc site of Nkang, Southern Cameroon, are presented, which includes charcoal, phytoliths, molluscs and animal bones.
132 citations
TL;DR: The external morphology and anatomy of the seeds of some 90 genera and some 200 species of the Cruciferae have been investigated and it is difficult or impossible to distinguish between some genera on seed characters, but the present investigation provides no support for tribal divisions within the CruCiferae.
131 citations
TL;DR: Evidence showed that the trichome number was not fixed at the time of leaf emergence and a striking monoterpene composition variability was present among individual trichomes and between different parts of the leaf.
Abstract: The trichome number and the variability in mono and sequisterpene distribution of peltate trichomes within a leaf was investigated during development of peppermint (Mentha×piperita L.) leaves. A larger number of peltate trichomes was initiated on adaxial epidermises than abaxial epidermises, but during leaf development a greater gland number was produced on abaxial epidermises. Evidence showed that the trichome number was not fixed at the time of leaf emergence. On both epidermises, the trichome distribution was found to change with its position on the leaf. A striking monoterpene composition variability was present among individual trichomes and between different parts of the leaf. Different rates of peltate trichome development and distribution as well as significant differences in trichome number and density were found between the epidermises. A clear and opposite trend was found between menthone and menthol percentages during development. Menthone and menthol were also found to be present in larger amounts on adaxial epidermises, whereas neomenthol and isomenthol had highest percentages on abaxial epidermises. Of the total oil collected from peltate trichomes, 60%, was composed of menthone. isomenthol, menthol and neomenthol and of the remaining 40 %, more than half was represented by other mono and sesquiterpenes while the final percentage was made up of a few unidentified early eluting compounds of high Volatility.
131 citations
TL;DR: The results indicate that mite-domatia association represents a relationship of comparable scope to plant-ant associations mediated by specialized plant structures such as extrafloral nectaries, food bodies and specialized domatia, and suggest that sociality is not a necessary prerequisite for widespread and diverse mutualisms between arthropods and plants.
Abstract: Leaf domatia, specialized chambers in the vein axils on the underside of leaves of many plant species, have remained an enigma for over a century. In this study we show a strong association between foliar domatia and mites in 37 plant species in Australasia. Overall, mites accounted for 91% of the arthropods observed in domatia. Across all species, a median of 51% of domatia were occupied and 71% of leaves showed mite evidence in domatia. The level of mite association did not depend on domatia type (pit, pouch, pocket, or tuft) or provenance (Papua New Guinea, Queensland, Victoria, or New Zealand). Mite association with domatia commonly varied between plant species, between individuals within species, and between shoots within individuals. The leaf developmental stage probably explains much of the variation in association for many of these species. The presence of a variety of life history stages of mites within domatia indicates that these structures act as shelters for development and reproduction. Furthermore, in 12 of 13 plant species examined, domatia concentrate mites in particular locations on the leaf. Mite taxa that we classify as largely predaceous (e.g. phytoseiids, stigmaeids and tydeids) or fungivorous (e.g. acarids and oribatids) were most common in domatia and dominated the association in 21 of 24 plant species in which the relative abundance of herbivorous, fungivorous and predaceous groups was quantified.
We evaluate hypotheses that explain the role of leaf domatia, including non-functional hypotheses (e.g. architectural constraints), physiological function (e.g. gas exchange and water uptake), bacterial symbiosis and antagonistic and mutualistic associations with mites. Our quantitative results confirm anecdotal accounts of mite association with leaf domatia and are most consistent with Lundstroem's century-old hypothesis of plant-mite mutualism in which leaf domatia billet predaceous and fungivorous mites that prey on plant enemies. Leaf domatia are widespread among woody angiosperms and abundant in many temperate and tropical regions of Australasia. Mites, an ancient group of arthropods whose diversity and abundance parallels that of insects, are likely to be important selective agents on terrestrial plants. Our results (1) indicate that mite-domatia association represents a relationship of comparable scope to plant-ant associations mediated by specialized plant structures such as extrafloral nectaries, food bodies and specialized domatia; (2) suggest that sociality is not a necessary prerequisite for widespread and diverse mutualisms between arthropods and plants; and, (3) extend the diversity of organisms that produce specialized mite ‘houses’ from lizards, and wasps and bees to woody angiosperms.
131 citations
TL;DR: Malvaceae is redefined to refer to the most recent common ancestor of plants previously considered to be “Tiliaceae,” “Sterculiaceae, “Bombacaceae” and Malvaceae, and all of the descendants of that ancestor.
Abstract: We report a phylogenetic analysis of “core” Malvales (Tiliaceae, Sterculiaceae, Bombacaceae, and Malvaceae) based on morphological, anatomical, palynological, and chemical features. The results of the analyses lead to the conclusion that Tiliaceae, Sterculiaceae, and Bombacaceae, as variously delimited, are paraphyletic; only the Malvaceae are likely monophyletic. The genera of “core” Malvales form a well-defined clade. Genera of “Tiliaceae” constitute the basal complex within “core” Malvales. The “Sterculiaceae” (most genera)+ “Bombacaceae” + Malvaceae form a clade on the basis of a monadelphous androecium; “Bombacaceae”+ Malvaceae also form a clade, which is diagnosable on the basis of monoloculate anthers. It is clear that the traditional classification, with its arbitrarily delimited evolutionary grades, is unsatisfactory, especially if one seeks to reflect phylogeny accurately. Thus, Malvaceae is redefined to refer to the most recent common ancestor of plants previously considered to be “Tiliaceae,” “Sterculiaceae,” “Bombacaceae,” and Malvaceae, and all of the descendants of that ancestor. This broadly circumscribed Malvaceae can be diagnosed by several presumed synapomorphies, but we draw special attention to the unusual floral nectaries that are composed of densely packed, multicellular, glandular hairs on the sepals (or less commonly on the petals or androgynophore).
130 citations