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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01 Jan 2016
19 citations
TL;DR: A revision of Octoknema Pierre is provided, based on morphological data gathered from a study of herbarium specimens and observations in the field, including six new species: O. bakossiensis Gosline & Malécot, O. chailluensis MalÉcot & Gosline,O.
Abstract: A revision of Octoknema Pierre is provided, based on morphological data gathered from a study of herbarium specimens and observations in the field. Fourteen species of Octoknema are recognised including six new species: O. bakossiensis Gosline & Malecot, O. belingensis Gosline & Malecot, O. chailluensis Malecot & Gosline, O. kivuensis Gosline & Malecot, O. mokoko Gosline & Malecot and O. ogoouensis Malecot & Gosline. Data are given for four additional poorly known taxa (Octoknema species A, B, C and D).
19 citations
TL;DR: Crystalline inclusions were observed in more than 50%, silica in nearly 20% of about 1500 wood specimens representing ±750 species from 40 genera of the laurel family, with taxonomic implications on the specific, generic and suprageneric level.
Abstract: Crystalline inclusions were observed in more than 50%, silica in nearly 20% of about 1500 wood specimens representing ±750 species from 40 genera of the laurel family. Both types of inorganic cell deposits are described and classified with regard to composition, habit, size, degree of isolation and location. Their diagnostic value and taxonomic implications on the specific, generic and suprageneric level are discussed with respect to intra as well as extrafamiliar relationships.
19 citations
TL;DR: New data suggest the presence of more than one Pseudofrenelopsis species in the Aptian taphoflora of the Araripe Basin and further support the taxonomic placement of B. obesum within Araucariaceae.
Abstract: Pseudofrenelopsis and Brachyphyllum are two conifers that were part of the Lower Cretaceous (Aptian) taphoflora of the Crato Formation, Araripe Basin, northeastern Brazil. The former genus includes, so far, P. capillata and indeterminate species, whilst the latter is mainly represented by B. obesum, the most common plant megafossil recovered from that stratigraphic unit. Here, the stem and leaf anatomy of Pseudofrenelopsis sp. and B. obesum specimens is revisited, including the first report of some epidermal and vascular traits for both taxa from the Crato Formation. Along with its paleoecological significance, the new data suggest the presence of more than one Pseudofrenelopsis species in the Aptian taphoflora of the Araripe Basin and further support the taxonomic placement of B. obesum within Araucariaceae.
19 citations
TL;DR: Wood characters in the context of Caryophyllales are evaluated and characters that may be synapomorphies of clades within this group are suggested, e.g., minute lateral wall pits apparently characterize the clade comprising Plum baginaceae, Polygonaceae, Frankeniaceae, and Tamaricaceae.
Abstract: Stem and root anatomy of Hypericopsis persica is evaluated in light of molecular data reconstructing Hypericopsis within a clade of Asian Frankenia. No anatomical information contradicts the idea that Hypericopsis should be subsum ed within Frankenia. Anatomy in the two genera is comparable, taking into account the unusual habit of Hypericopsis , which consists of slender, short-lived shoots from a long-lived caudex, whereas most species of Frankenia are small shrubs with long-lived shoots. Wood of the slender stem s of Hypericopsis is similar to twig wood of the related Frankenia hirsuta in qualitative and quantitative features but differs from mature wood of other species of Frankenia described in previous studies in having smaller cells and little storying. Wood of Hypericopsis is rayless and is made up mostly of libriform fibers and vessel elements associated with vasicentric tracheids. Axial parenchyma is occasional at the margins of growth rings. We briefly evaluate wood characters in the context of Caryophyllales s.l. and suggest characters that may be synapomorphies of clades within this group, e.g., minute lateral wall pits apparently characterize the clade comprising Plum baginaceae, Polygonaceae, Frankeniaceae, and Tamaricaceae. That vasicentric tracheids elongate considerably beyond the lengths of the vessel elements with which they are associated is cited as a distinct ontogenetic difference between these cell types. Likewise, num erous vessel elem ents comparable in diameter to vasicentric tracheids were observed. These observations are offered as reasons to reject the concept of vasicentric tracheids as simply vessel elements that are too narrow for the formation of perforation plates.
19 citations