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Journal ArticleDOI

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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Journal ArticleDOI
TL;DR: The gap between morphological and ontogenetical classifications has been bridged and any other new type can be included and all the possibilities for the introduction of supplementary data are left open.
Abstract: The compilation of new data on stomatal ontogeny from the literature and the finding of a rather unknown type inMarcgravia have shown the need of a new classification of the ontogenetic types of stomata. Pant (1965) recognized 10 main types; this number is now enlarged to 26 and a modified terminology is chosen. From the name of each type not only the ontogenetical pattern but also the morphological nature of the adult stoma can be deduced. Thus the gap between morphological and ontogenetical classifications has been bridged.

153 citations

Book ChapterDOI
TL;DR: The various plant environmental, and chemical factors which affect absorption are examined in this review, and a variety of pesticides is considered, as well as certain growth regulators and other substances which are not, strictly speaking, “pesticides.
Abstract: Plants are sprayed and dusted with chemicals for numerous reasons. Some of the chemicals applied to plants exert their influence simply by remaining on the foliage surface; others must be absorbed and perhaps translocated before their activity is realized. Many of the compounds used have a mammalian toxicity less than that of table salt, whereas others exceed strychnine in toxicity. Likewise, many are relatively non-phytotoxic but others kill plants readily. Possible foliar residues which may be left by various pesticides are of course influenced by both absorption characteristics and metabolic breakdown. The various plant environmental, and chemical factors which affect absorption are examined in this review. A variety of pesticides is considered, as well as certain growth regulators and other substances which are not, strictly speaking, “pesticides.” A limited consideration is also given to recent findings relating to penetration of inorganic ions, where the mechanisms involved may bear certain similarities to the penetration of some organic substances which also ionize or hydrolyze during the course of their penetration. Because of this broad coverage, space precludes detailed discussions of all aspects of absorption and of associated structural relationships. These subjects are developed quite fully in many of the reviews listed below and in the introductions to some of the specific sections in this report. Also, only foliar absorption and movement within the leaf mesophyll and veins are considered. Long distance transport in the vascular system of the stems and roots is not included, since several excellent reviews and monographs on this subject have recently been published or are in preparation.

152 citations

Journal ArticleDOI
TL;DR: Onagraceae constitute a clearly marked family of the order Myrtales, comprising 7 tribes, 17 genera, and about 674 species, nearly all of the trees and shrubs in the family, but only about one third of the annuals and perennial herbs, are outcrossing.
Abstract: Onagraceae constitute a clearly marked family of the order Myrtales, comprising 7 tribes, 17 genera, and about 674 species. Of these species, about 42% are outcrossed, 52% self-pollinated, and another 6% contain both sorts of breeding systems within a single species. In outcrossed species, the stigma is always elevated above the anthers at anthesis. The three principal modes of enforcing outcrossing are protandry, in Epilobium, Clarkia, and Lopezia (with protogyny in most species of Circaea); male sterility, independently derived in four small sections of Fuchsia; and genetic self-incompatibility, found in at least 76 species, representing 4 of the 7 tribes and 10 of the 17 genera of the family. Nearly all of the trees and shrubs in the family, but only about one third of the annuals and perennial herbs, are outcrossing. Clarkia is an example of an entirely annual genus that consists predominantly of outcrossing species, whereas Ludwigia and Epilobium are predominantly perennial genera that consi...

152 citations

Journal ArticleDOI
TL;DR: A two-step parsimony analysis on 125 rbcL sequences to clarify the composition of Malvales, to determine the relationships of some controversial families, and to identify the placement of the MalVales within Rosidae strongly support the monophyly of the core malvalean families.
Abstract: The order Malvales remains poorly circumscribed, despite its seemingly indisputable core constituents: Bombacaceae, Malvaceae, Sterculiaceae, and Tiliaceae. We conducted a two-step parsimony analysis on 125 rbcL sequences to clarify the composition of Malvales, to determine the relationships of some controversial families, and to identify the placement of the Malvales within Rosidae. We sampled taxa that have been previously suggested to be within, or close to, Malvales (83 sequences), plus additional rosids (26 sequences) and nonrosid eudicots (16 sequences) to provide a broader framework for the analysis. The resulting trees strongly support the monophyly of the core malvalean families, listed above. In addition, these data serve to identify a broader group of taxa that are closely associated with the core families. This expanded malvalean clade is composed of four major subclades: (1) the core families (Bombacaceae, Malvaceae, Sterculiaceae, Tiliaceae); (2) Bixaceae, Cochlospermaceae, and Sphaerosepalaceae (Rhopalocarpaceae); (3) Thymelaeaceae sensu lato (s.l.); and (4) Cistaceae, Dipterocarpaceae s.l., Sarcolaenaceae (Chlaenaceae), and Muntingia. In addition, Neurada (Neuradaceae or Rosaceae) falls in the expanded malvalean clade but not clearly within any of the four major subclades. This expanded malvalean clade is sister to either the expanded capparalean clade of Rodman et al. or the sapindalean clade of Gadek et al. Members of Elaeocarpaceae, hypothesized by most authors as a sister group to the four core malvalean families, are shown to not fall close to these taxa. Also excluded as members of, or sister groups to, the expanded malvalean clade were the families Aextoxicaceae, Barbeyaceae, Cannabinaceae, Cecropiaceae, Dichapetalaceae, Elaeagnaceae, Euphorbiaceae s.l., Huaceae, Lecythidaceae, Moraceae s.l., Pandaceae, Plagiopteraceae, Rhamnaceae, Scytopetalaceae, Ulmaceae, and Urticaceae. The order Malvales, as traditionally circumscribed, includes four core families, Bombacaceae (;250 spp.), Malvaceae (1500 spp.), Sterculiaceae (1000 spp.), and Tiliaceae (400 spp.), plus from one to eight other families depending upon author (Takhtajan, 1987, 1997; Cronquist, 1988; Dahlgren, 1989; Thorne, 1992). Considering only the core four families, the order comprises predominantly woody and tropical trees, including several economically important genera such as cotton (Gossypium

147 citations

Journal ArticleDOI
TL;DR: In this paper, phylogenetic relationships between Magnoliales and Myristicaceae were investigated using a morphological matrix (115 characters) and multiple molecular data sets (seven variable chloroplast loci and five more conserved genes; 14 536 aligned nucleotides).

147 citations