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: The topologies obtained by the different methods were completely congruent, and bootstrapping strongly supported the division of the family Betulaceae into two major clades, Betuleae (Alnus and Betula) and Coryleae (other members).
Abstract: Estimations of phylogenies from morphological and molecular data often show contrasting results. We compared morphological and molecular phylogenies in an ancient family of woody dicots, the Betulaceae (birch family). The phylogeny of the family was estimated from parsimony analysis of morphological characters in the genera Alnus, Betula, Carpinus, Corylus, Ostrya, and Ostryopsis and from parsimony and distance-matrix analyses of DNA sequences of the chloroplast gene encoding the large subunit of ribulose- 1 ,Sbiphosphate carboxylase ( rbcL) in the genera Alnus, Betula, Carpinus, Corylus, and Ostrya and in two outgroups, Quercus and Liquidambar. The topologies obtained by the different methods were completely congruent, and bootstrapping strongly supported the division of the family Betulaceae into two major clades, Betuleae (Alnus and Betula) and Coryleae (other members). Only slightly more homoplasy was present in the rbcL sequence data set than in the morphological set. Relative-rate tests indicated that the Coryleae clade had a faster rate of rbcL evolution than did the Betuleae clade. Heterogeneity of rates of morphological evolution also paralleled those for rbcL.
90 citations
TL;DR: The hypothesis that angiosperms are primitively vesselless was tested in the context of a cladistic analysis of selected families of the Magnoliidae, Ra- nunculidae, and Hamamelididae and it is suggested that the xylem of these genera is paedomorphic.
Abstract: The hypothesis that angiosperms are primitively vesselless was tested in the context of a cladistic analysis of selected families of the Magnoliidae, Ra- nunculidae, and Hamamelididae. Results of this analysis show that the most parsi- monious explanation of the absence of vessels in dicotyledons is that in all instances it is a derived feature. This conclusion is supported by three taxon out-group com- parisons and does not alter our well-founded understanding of vessel member evo- lution within the angiosperms. I suggest that presence of vessel members with sca- lariform perforation plates and scalariform intervascular pitting, such as those in Austrobaileya, is the "primitive" condition within the angiosperms. I also suggest that in the earliest angiosperms vessels were restricted to secondary xylem. Absence of vessels in the eleven extant genera of "primitive" woody dicotyledons is a secondary loss, and it is suggested that the xylem of these genera is paedomorphic. Perhaps one of the most widely accepted hypotheses regarding the evolution of angiosperms is that they are primitively vesselless (Bailey 1957a). That is, absence of vessels in the xylem of taxa of the woody, dicotyledonous families Winteraceae, Chloranthaceae, Amborellaceae, Trochodendraceae, and Tetracentraceae (table 1), and perhaps the her- baceous Nymphaeales, represents retention of a primitive feature.
90 citations
TL;DR: Differences in proportions of parts of the ovules in Anacardiaceae and Burseraceae are linked with the different direction of ovule curvature, which may represent a synapomorphy or apomorphic tendency for the three families.
90 citations
Book•
31 Jul 1984
TL;DR: This chapter discusses Morphology, Chemistry, and Genetics of Gossypium Adaptations to Pests, and changes in the Levels of Plant Secondary Metabolite Production Under Water and Nutrient Stress.
Abstract: 1. Introductory Chapter.- 2. Putrescine and Inorganic Ions.- 3. Phytochemical Aspects of Osmotic Adaptation.- 4. Thigmomorphogenesis: Callose and Ethylene in the Hardening of Mechanically Stressed Plants.- 5. Stress and Secondary Metabolism in Cultured Plant Cells.- 6. Temperature Stress and Lipid Modification.- 7. Morphology, Chemistry, and Genetics of Gossypium Adaptations to Pests.- 8. Bioregulation of Plant Constituents.- 9. Production of Resins by Arid-Adapted Astereae.- 10. Changes in the Levels of Plant Secondary Metabolite Production Under Water and Nutrient Stress.- Species Index.
88 citations
TL;DR: Two sister clades Saururaceae and Piperaceae, there are parallel reduction trends in floral organ number and in the sequence of floral organ initiation, and Numerous autapomorphies support Peperomia as a distinct and specialized offshoot within Piperaceae.
Abstract: Morphological and developmental evidence is utilized in a phylogenetic analysis of Piperales. Best resolution of trees was obtained by combining ontogenetic data with conventional morphological data. Floral ontogeny provides a means to determine homology among character states as well as to provide additional characters not observable in mature flowers. Both Lundberg and outgroup rooting were performed using a hypothetical ancestor defined by general ontogenetic states in the former and by five taxa presumably related to the ingroup in the latter. Polarization of character states via ontogenetic generality principles is congruent with outgroup polarization. Saururaceae and Piperaceae are each monophyletic. Saururaceae are supported by three synapomorphies, with Saururus as the basal taxon. The other three saururaceous genera (Anemopsis, Houttuynia, Gymnotheca) share the derived character slates of syncarpy, stamen-carpel adnation, and an inferior or half-inferior ovary. Piperaceae are supported by seven synapomorphies with Zippelia as the basal taxon. Six other synapomorphies unite the remaining Piperaceae suggesting that Macropiper and Pothomorphe are specialized offshoots of the morphologically variable Piper. Numerous autapomorphies support Peperomia as a distinct and specialized offshoot within Piperaceae. Within the sister clades Saururaceae and Piperaceae, there are parallel reduction trends in floral organ number and in the sequence of floral organ initiation.
88 citations