Topic
Conceptacle
About: Conceptacle is a research topic. Over the lifetime, 82 publications have been published within this topic receiving 1516 citations.
Papers published on a yearly basis
Papers
TL;DR: The mode of division of vegetative cells, formation of spermatangial parent cells, initiation of the carpogonial branch apparatus, and formation of tetrasporangial initials are homologous developmental processes that are documented for the first time in the type species of the economically important family Gracilariaceae, Gracilaria verrucosa from the British Isles.
Abstract: The mode of division of vegetative cells, formation of spermatangial parent cells, initiation of the carpogonial branch apparatus, and formation of tetrasporangial initials are homologous developmental processes that are documented for the first time in the type species of the economically important family Gracilariaceae, Gracilaria verrucosa (Hudson) Papenfuss from the British Isles. G. verrucosa is characterized by a supporting cell of intercalary origin that bears a 2-celled carpogonial branch flanked by two sterile branches, direct fusion of cells of sterile branches onto the carpogonium, formation of an extensive carpogonial fusion cell through the incorporation of additional gametophytic cells prior to gonimoblast initiation, gonimoblast initials produced from fusion cell lobes, schizogenous development of the cytocarp cavity, inner gonimoblast cells producing tubular nutritive cells that fuse with cells of the pericarp or floor of the cystocarp, absence of cytologically modified tissue in the floor of the cystocarp, and carposporangial initials produced in clusters or irregular chains. Spermatangial parent cells are generated in flaments from intercalary cortical cells that line an intercellular space forming a ‘pit’ or ‘conceptacle’. Tetrasporangial initials are transformed from terminal cells derived through division of an outer cortical cell. Tetrasporangia are cruciately divided.
The Gracilariaceae is removed from Gigartinales and transferred to the new order Gracilariales. Their closest living relatives appear to be agarophytes belonging to the Gelidiales and Ahnfeltiales.
148 citations
TL;DR: It is concluded that Spongites and Hydrolithon are distinct genera of the Corallinaceae (Rhodophyta), and Porolithon onkodes is considered to be a heterotypic synonym.
Abstract: Studies of tetrasporangial conceptacle development and anatomy have led to the conclusion that Spongites and Hydrolithon (of which Porolithon is considered to be a heterotypic synonym) are distinct genera of the Corallinaceae (Rhodophyta). In Australian populations of Hydrolithon reinboldii (Weber van Bosse et Foslie) Foslie, the type species of Hydrolithon, and Porolithon onkodes (Heydrich) Foslie, the type species of Porolithon, the tetrasporangial conceptacle pore canal is lined by a ring of conspicuous, elongate cells that arise from filaments interspersed amongst sporangial initials, do not protrude into the canal, and are oriented more or less perpendicularly to the roof surface. In Spongites fruticulosus Kutzing, the type species of Spongites, the pore canal is lined by cells that arise from peripheral roof filaments, protrude into the canal and are oriented more or less parallel to the roof surface. Tetrasporangial conceptacle development in Hydrolithon reinboldii and Porolithon onkodes i...
84 citations
TL;DR: In the studied material of the Late Eocene Austrian Molasse Zone Lithoporella, Neogoniolithon, Spongites, Phymatolithon and Sporolithon are identified and described applying features of neontological taxonomic concepts.
Abstract: . Traditionally, different diagnostic characters have been used in the identification of fossil and Recent coralline algal genera. The taxonomy of fossil coralline algae has focused on well calcified features such as basal filaments and conceptacle perforation. In contrast, the taxonomy of Recent material uses a combination of several features with a low fossilization potential, such as epithallial cells and structures of sexual reproductive organs. In the studied material of the Late Eocene Austrian Molasse Zone Lithoporella, Neogoniolithon, Spongites, Phymatolithon and Sporolithon are identified and described applying features of neontological taxonomic concepts. These features are: (1) the arrangement of basal filaments; (2) the occurrence of cell fusions; (3) the relative length of subepithellial initials; (4) the conceptacle perforation; (5) the orientation of filaments around the conceptacle pore; and (6) the type of conceptacle roof formation. Some of these features were thought to be unpresentable in fossil material until recently. The fossilization potential of diagnostic features and the identification of the documented genera and species are discussed in detail. Moreover, a checklist for the description of fossil taxa is provided.
75 citations
TL;DR: The species and the development of male and female-carposporangial conceptacles and tetrasporangIAL compartments and sori are described in detail for the first time and differences between the Sporolithaceae and the Corallinaceae are reconsidered in relation to new data on S. durum.
Abstract: Sporolithon (Sporolithaceae, Corallinales) is represented in southern Australia by S. durum (Foslie) Townsend et Woelkerling, comb. nov. The species and the development of male and female-carposporangial conceptacles and tetrasporangial compartments and sori are described in detail for the first time. Information on etymology, collections examined, distribution, seasonality and habit and comparisons with other species is also included. Published records of S. erythraeum from southern Australia have not been substantiated. Two further species have been reported under the generic name Archaeolithothamnion. Archaeolithothamnion australasicum is a species of uncertain status, while A. mirabile is conspecific with Lithothamnion muelleri Lenorrnand ex Rosanoff. Differences between the Sporolithaceae and the Corallinaceae, and the delimitation of genera within the Sporolithaceae, are reconsidered in relation to new data on S. durum. The Sporolithaceae is characterised by tetrasporangia that produce cruciately arranged spores and develop within calcified sporangial compartments, while the Corallinaceae is characterised by tetrasporangia that produce zonately arranged spores that do not develop in calcified sporangial compartments. Two genera of Sporolithaceae are recognised: Heydrichia, in which tetrasporangial compartments are enclosed by modified filaments to form sporangial complexes; and Sporolithon, in which tetrasporangial compartments are not enclosed by modified filaments and sporangial complexes are absent. The concepts of conceptacle and sorus also are reconsidered.
65 citations
TL;DR: The morphology of these three taxa is described with emphasis on epithallia, host-epiphyte development, and conceptacle formation, and a new tribe in the Melobesioideae, Phymatolitheae, is described.
Abstract: Three species of crustose coralline algae growing almost exclusively on articulated corallines on the west coast of North America have been grouped together in the genus Polyporolithon (Mason, 1953). However, studies of their anatomy and reproduction reveal that they belong to different genera, and they are herein treated as Clathromorphum parcum, Mesophyllum conchatum, and Neopolyporolithon reclinatum, Neopolyporolithon being newly described in this paper. The morphology of these three taxa is described with emphasis on epithallia, host-epiphyte development, and conceptacle formation. Notable are the way in which early development of C. parcum is related to the growth of its host and the manner in which spermatangial conceptacles originate in C. parcum and N. reclinatum. A new tribe in the Melobesioideae, Phymatolitheae, is described. The presence or absence of genicula, of tetrasporangial plugs, and of secondary pit-connections are important characteristics distinguishing the seven subfamilies ...
55 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 2 |
| 2019 | 1 |
| 2018 | 1 |
| 2017 | 1 |
| 2016 | 1 |
| 2015 | 1 |