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 persistence of Asclepias syriaca L. as a weed is related to its ability to propagate vegetatively by the development of adventitious buds on roots by developing root buds that arise on the main root.
Abstract: The persistence of Asclepias syriaca L. as a weed is related to its ability to propagate vegetatively by the development of adventitious buds on roots. These root buds arise on the main root and upper lateral roots within 25 days of the establishment of seedlings and are generally associated with the bases of lateral roots. A study of root anatomy shows that the origin of these buds is endogenous, in the pericycle and (or) its derivatives. No root buds are initiated until after lateral roots have developed and some cambial activity has begun. Vascular connections from the bud to the stele of the parent root, or an associated lateral root, are made at an early stage of bud development.
19 citations
TL;DR: Current opinion that Salvadoraceae are a sister family to Bataceae is supported by wood anatomy: they share such features as bands of mostly nonsubdivided axial parenchyma cells, wide multiseriate rays, and and storied structure.
Abstract: CARLQUIST, S. (Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105). Wood and bark anatomy of Salvadoraceae: relationships, ecology, histology of interxylary phloem. J. Torrey Bot. Soc. 129:10-20. 2002. Quantitative and qualitative data are presented for stem wood of one species each of Azima, Dobera, and Salvadora and for root wood of Salvadora. The liquid-preserved material of Salvadora permitted analysis of interxylary phloem: abaxial to most strands a "residual meristem" adds sieve-tube elements and companion cells to each strand, crushing earlier-formed phloem. Current opinion that Salvadoraceae are a sister family to Bataceae is supported by wood anatomy: they share such features as bands of mostly nonsubdivided axial parenchyma cells, wide multiseriate rays, and and storied structure. Nonbordered perforation plates, found also in other Capparales, are newly reported for Salvadoraceae. Koeberliniaceae have tracheids, Bataceae fibertracheids, thought more primitive than the libriform fibers of Salvadoraceae. Wood of Azima is moderately mesomorphic, perhaps because it grows near beaches where saline or brackish water is available to roots; Dobera and Salvadora have highly xeromorphic wood. The terms "foraminate included phloem" and "concentric included phloem" are misnomers and must be rejected.
19 citations
TL;DR: The Didymelaceae are to be placed in the relationship of the Euphorbiaceae, Buxaceae and Thymelaeaceae which show a mosaic pattern of reciprocal character combinations and similarities in patterns of pollen morphological variation.
Abstract: Der Pollen von Didymeles madagascariensis WILLD. wurde licht- und rasterelektronen-mikroskopisch untersucht. Es werden eine detaillierte Beschreibung und Abbildungen gegeben.
Die Bedeutung der Pollenmerkmale fur die Erkenntnis der systematischen Stellung dieser monotypischen Familie wird diskutiert.
Die Pollenmorphologie schliest eine engere Verwandtschaft mit den Leitneriales und anderen Vertretern der Hamamelididae aus, was durch Blattnervatur-Typen und Testa-merkmale zu unterstutzen ist.
Die Didymelaceae sind in die Verwandtschaft der Euphorbiaceae, Buxaceae und Thymelaeaceae einzuordnen, die ein Mosaik wechselseitiger Merkmalsverknupfungen und Ahnlichkeiten im Muster der pollenmorphologischen Variation zeigen.
Die reticulaten Merkmalsbeziehungen, die fur eine gemeinsame Abstammung dieser Gruppe sprechen, scheinen sich in Blattnervatur-Typen, in anatomischen, embryologischen und florengenetischen Aspekten widerzuspiegeln, die weiterer Untersuchungen bedurfen.
Pollen grains of Didymeles madagascariensis were examined by light and scanning electron microscopy and a detailed description and micrographs are presented.
The significance of pollen characters for the recognition of the systematic position of this monotypic family is discussed.
Pollen morphology excludes closer relationships with the Leitneriales and other representatives of the Hamamelididae which is supported by leaf venation types and testa characters.
The Didymelaceae are to be placed in the relationship of the Euphorbiaceae, Buxaceae and Thymelaeaceae which show a mosaic pattern of reciprocal character combinations and similarities in patterns of pollen morphological variation.
The reticulate character correlations, speaking in favor of a common ancestry of this group, seem to be reflected in leaf venation types, in anatomical, embryological and floral genetical aspects which deserve further studies.
19 citations
TL;DR: The results show that the terminal structure in Gunnera is a flower rather than a pseudanthium, and propose vegetative and floral putative synapomorphies for the sister-group relationship between Gunneraceae and Myrothamnaceae.
19 citations
TL;DR: Anatomical evidences suggest that Sanango is most closely related to the Scrophulariales, sharing many important features with the Gesneriaceae.
Abstract: Summary was undertaken in an attempt to help clarify the relationships of the genus. Detailed descriptions of leaf, stem, nodal, wood, and floral anatomy are presented. Wood is characterized by a combination of solitary and grouped vessels with elements having few-barred scalariform perforation plates, imperforate tracheary elements with very reduced pit borders, exceptionally tall and broad hetero- cellular rays, and vasicentric axial parenchyma. Of special interest is the presence in Sanango of a very uncommon multilacunar nodal structure having split-lateral traces. Stems possess cortical vascular bundles. Leaf stomata are anisocytic and distributed in clusters on the undersurface of the lamina. Anatomical evidences suggest that Sanango is most closely related to the Scrophulariales, sharing many important features with the Gesneriaceae.
19 citations