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 development and plasticity of leaf venation and its adaptation across environments globally, and a new global data compilation indicating trends relating vein length per unit area to climate, growth form and habitat worldwide are described.
Abstract: The design and function of leaf venation are important to plant performance, with key implications for the distribution and productivity of ecosystems, and applications in paleobiology, agriculture and technology. We synthesize classical concepts and the recent literature on a wide range of aspects of leaf venation. We describe 10 major structural features that contribute to multiple key functions, and scale up to leaf and plant performance. We describe the development and plasticity of leaf venation and its adaptation across environments globally, and a new global data compilation indicating trends relating vein length per unit area to climate, growth form and habitat worldwide. We synthesize the evolution of vein traits in the major plant lineages throughout paleohistory, highlighting the multiple origins of individual traits. We summarize the strikingly diverse current applications of leaf vein research in multiple fields of science and industry. A unified core understanding will enable an increasing range of plant biologists to incorporate leaf venation into their research.
560 citations
Cites background from "Anatomy of the Dicotyledons."
...In the large veins of most angiosperms, the phloem is abaxial to the xylem (Esau, 1977), but species in at least 27 families also have adaxial phloem (Metcalfe & Chalk, 1950)....
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TL;DR: Thome, Robert F. as mentioned in this paper presented the latest revision of the classification of the Class Angiospermae and replaces my 1983 and more recent 1992 synopses. And a new phyletic "shrub" replaces earlier versions, and attempts to indicate visually relative sizes and relationships among the superorders, orders, and suborders.
Abstract: Thome, Robert F. (Rancho Santa Ana Botanic Garden, Claremont, CA 91711). Classification and geography of the flowering plants. Bot. Rev.58(3): 225–348. 1992.—This treatment of the flowering plants is the latest revision of my classification of the Class Angiospermae and replaces my 1983 and more recent 1992 synopses. An update is necessary because so much new information has been published in the last decade pertinent to the classification of the flowering plants. About 870 such recent books, monographs, and other botanical papers are cited in the Introduction, listed primarily by the botanical discipline that they represent. Also considerable changes in my classification have been necessitated by my narrowed family- and ordinal-gap concepts, acceptance of the ending “-anae” for superorders in place of the traditional but inappropriate “-iflorae,” and acceptance of more prior or more widely used names for the categories above the family. A new phyletic “shrub” replaces earlier versions, and attempts to indicate visually relative sizes and relationships among the superorders, orders, and suborders. One table includes a statistical summary of floweringplant taxa: ca. 233,900 species of 12,650 genera, 437 families, and 708 subfamilies and undivided families in 28 superorders, 71 orders, and 71 suborders of Angiospermae. Three other tables summarize the known indigenous distribution of the families and subfamilies of angiosperms about the world. The synopsis lists the flowering plant taxa from the class down to the subfamily (and in Asteraceae down to the tribe) with indication of the degree of confidence I place in the circumscription and placement of each category above the subfamily, the best available estimates of the number of genera and species for each category, and the known indigenous distribution of each subfamily and family. Table V lists alphabetically the geographical abbreviations used in the synopsis. The extensive bibliography of recent literature should be helpful to those persons interested in the classification of the flowering plants.
518 citations
TL;DR: Relationship to Physical Factors, Parasites and Pathogens, and Functions Ascribed to Pubescence are reviewed.
Abstract: General distributkm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 3 Trichomes and lhe lndumentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 4 T h e Nature of Trichomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 5 The Nature of the lndumentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 7 Patterns o f O c c u r r e n c e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 7 Environmental Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 8 Classifications of Pubescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 0 Functions Ascribed to Pubescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 1 Relationship to Physical Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 B o u n d a r y Layer Effects on Transpiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 1 Short Wave Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 2 L o n g Wave Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 3 Relationship t o B i o t i c F a c t o r s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 4 Predators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 5 Parasites and Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 7 Relationship to Physiological Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 8 Material E x c h a n g e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 8 Metabolic R e g u l a t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 0 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 0 Z u s a m m e n f a s s u n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 3 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 3
482 citations
TL;DR: Combined analyses of morphological and molecular data generally yield the same topologies as molecular analyses, but morphology overcomes weak molecular evidence in indicating that Chloranthaceae belong just above the basal grade, that monocots are related to Piperales, and that Lauraceae are linked with Hernandiaceae.
Abstract: We have amassed structural data for 108 characters and 52 taxa of magnoliids and basal monocots and eudicots, including observations by P. K. Endress and A. Igersheim on flowers. These data were analyzed separately and in combination with rbcL, 18S, and atpB sequences. Besides confirming agreements between previous analyses of both kinds of data (reduction of Magnoliales to six families; relation of Piperaceae, Saururaceae, Lactoris, and Aristolochiaceae), trees based on this data set show shifts toward molecular results (separation of Illiciaceae and Schisandraceae from Winteraceae and of Amborella, Austrobaileya, Trimeniaceae, and Chloranthaceae from Laurales; relation of Winteraceae and Canellaceae) plus continued conflicts (association of Chloranthaceae with Amborella and Trimeniaceae and of Nymphaeales with monocots). In cases where molecular and morphological trees conflict, combined analyses of morphological and molecular data generally yield the same topologies as molecular analyses, but morpholog...
368 citations
TL;DR: The results suggest that AS2 functions in the transcription of a certain gene(s) in plant nuclei and thereby controls the formation of a symmetric flat leaf lamina and the establishment of a prominent midvein and other patterns of venation.
Abstract: The ASYMMETRIC LEAVES2 (AS2) gene of Arabidopsis thaliana is involved in the establishment of the leaf venation system, which includes the prominent midvein, as well as in the development of a symmetric lamina. The gene product also represses the expression of class 1 knox homeobox genes in leaves. We have characterized the AS2 gene, which appears to encode a novel protein with cysteine repeats (designated the C-motif) and a leucine-zipper-like sequence in the amino-terminal half of the primary sequence. The Arabidopsis genome contains 42 putative genes that potentially encode proteins with conserved amino acid sequences that include the C-motif and the leucine-zipper-like sequence in the amino-terminal half. Thus, the AS2 protein belongs to a novel family of proteins that we have designated the AS2 family. Members of this family except AS2 also have been designated ASLs (AS2-like proteins). Transcripts of AS2 were detected mainly in adaxial domains of cotyledonary primordia. Green fluorescent protein-fused AS2 was concentrated in plant cell nuclei. Overexpression of AS2 cDNA in transgenic Arabidopsis plants resulted in upwardly curled leaves, which differed markedly from the downwardly curled leaves generated by loss-of-function mutation of AS2. Our results suggest that AS2 functions in the transcription of a certain gene(s) in plant nuclei and thereby controls the formation of a symmetric flat leaf lamina and the establishment of a prominent midvein and other patterns of venation.
363 citations