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: Identification of meristem activity and appreciation of varied ray manifestations are essential in understanding the ontogeny of stems in Amaranthaceae (which have recently been united with Chenopodiaceae).
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Journal Article•
TL;DR: This study was undertaken to investigate the morphological and anatomical properties of 5 annual taxa of Sideritis, including three species included in Burgsdorfia and Hesiodia sections.
Abstract: Sideritis L. (Lamiaceae) includes approximately 150 species of annual and perennial plants distributed mainly in the Mediterranean region. In Turkey, 44 species (55 taxa) are native. Three of these species (5 taxa) are annual and these taxa are included in Burgsdorfia and Hesiodia sections. This study was undertaken to investigate the morphological and anatomical properties of 5 annual taxa of Sideritis. Full descriptions and illustrations of these taxa are given, along with some additional information regarding their ecology and phytogeography. The anatomy of the leaf blade, midrib, and stem of the taxa are described and illustrated.
39 citations
TL;DR: The present work describes two new and unusual forms of raphide crystals from the tubers of Dioscorea polystachya—six-sided needles with pointed ends (Type V) and four- sided needles with beveled Ends (Type VI).
Abstract: Calcium oxalate crystals in higher plants occur in five major forms namely raphides, styloids, prisms, druses and crystal sand. The form, shape and occurrence of calcium oxalate crystals in plants are species- and tissue-specific, hence the presence or absence of a particular type of crystal can be used as a taxonomic character. So far, four different types of needle-like raphide crystals have been reported in plants. The present work describes two new and unusual forms of raphide crystals from the tubers of Dioscorea polystachya--six-sided needles with pointed ends (Type V) and four-sided needles with beveled ends (Type VI). Both of these new types of needles are distinct from the other four types by each having a surrounding membrane that envelopes a bundle of 10-20 closely packed thin crystalline sheets. The previously known four types of needles have solid or homogenous crystalline material, surrounded by a membrane or lamellate sheath called a crystal chamber. Only the Type VI crystals have beveled ends and the needles of the other five types have pointed ends.
39 citations
Cites background from "Anatomy of the Dicotyledons."
...The characteristic appearance, development and distribution of raphides, as well as other crystal shapes, have been used for taxonomic, pharmacognostic and toxicological purposes (Horner et al. 2012; Lampe and Fagerström 1968; Metcalfe and Chalk 1957; Sakai and Hanson 1974)....
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...The characteristic appearance, development and distribution of raphides, as well as other crystal shapes, have been used for taxonomic, pharmacognostic and toxicological purposes (Horner et al. 2012; Lampe and Fagerström 1968; Metcalfe and Chalk 1957; Sakai and Hanson 1974)....
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TL;DR: It is concluded that the evidence at present available gives little support to the retention of Griselinia in the same family as Cornus, though it is insufficient to settle the problem of its placement in any existing family.
Abstract: Summary New Zealand and South American species of Griselinia are compared with other genera of the Cornaceae, Araliaceae, and Escalloniacea. The main features examined are the morphology and anatomy of the shoot, the anatomy of the secondary xylem, and the vasculature of the flower. While Griselinia resembles all these families in some respects it does not fit within the boundaries of any one family. The implications of the complex inter-relationships between these and other families are discussed, and it is concluded that the evidence at present available gives little support to the retention of Griselinia in the same family as Cornus, though it is insufficient to settle the problem of its placement in any existing family.
39 citations
TL;DR: Observations are discussed with regard to the role of plasmodesmata in pit formation, and in the differentiation of the various cell types in secondary xylem.
Abstract: Developing pit membranes of secondary xylem elements in Drimys winteri, Fagus sylvatica, Quercus robur, Sorbus aucuparia, Tilia vulgaris and Trochodendron aralioides have been examined by transmission electron microscopy. Absence of plasmodesmata from the membranes of vessel elements and tracheids indicates that their pits develop independently of these structures. On the other hand, plasmodesmata are abundant in pit membranes between fibres, parenchyma cells, and combinations of these cell types in Fagus, Quercus and Tilia. In each case the plasmodesmata pass right through the developing pit membrane. In the case of Sorbus fibres, however, plasmodesmata were absent from the majority of pit membrane profiles seen in sections. Occasionally they were observed in large numbers associated with a swollen region on one side of the pit membrane between fibres and between fibres and parenchyma, radiating from a small area of the middle lamella. In the case of fibre to parenchyma pitting, this swelling was always found on the fibre side of the membrane, while on the other side a small number of plasmodesmata were present completing communication with the parenchyma cytoplasm. These observations are discussed with regard to the role of plasmodesmata in pit formation, and in the differentiation of the various cell types in secondary xylem. The significance their distribution may have for our understanding of xylem evolution is also discussed.
39 citations