Amphiroa beauvoisii

Plants of Amphiroa beauvoisii grow on the surface of rocks, attached on their undersides by a calcified and crustose base. From this base, erect axes grow up to long. The axes are made up of alternating segments of calcified sections called intergenicula and non-calcified sections called genicula. They branch out in a fan-like plane which is about tall, usually split into two distinct branches, but rarely split into three or four. However, they are sometimes wider towards their ends than at the base. The genicula typically are found where the branches split, or within of the split in the outward direction. Cellular characteristics When viewed under a scanning electron microscope, the outlines of cells on the surface of the intergenicula are clear. They consist of calcified ridges 3–9 μm wide which split to form two narrower ridges at the middle lamella. There are concavities 5–14 μm wide on the surface layer of the thallus which are covered in cup-like formations that are calcified, lip-like openings. On the flanks of the apices of the branches there are ridges which surround the apices or make arched lines across the flat side of the compressed branches. These ridges sometimes take the form of simple bands or randomly organized raised cells, while in other places they are made up of complexly overlapping layers of cells. They are harder to see the further away from the point of attachment they are, and on older intergenicula they disappear completely. Similar species Amphiroa beauvoisii is very similar in appearance to several other species in the genus Amphiroa, including A. anceps, A. gracilis, and A. klochkovana. It can be differentiated from A. gracilis and A. klochkovana by its intergenicula, which are almost all compressed or flat, and its genicula, which do not include decalcified cells from the peripheral region. It differs from A. anceps in its pore canals, in that the top of its canals are surrounded by a ring of large cells, while those of A. anceps are not. == Taxonomy ==

of A. beauvoisii at the Naturalis Biodiversity Center Jean Vincent Lamouroux provided the original description for Amphiroa beauvoisii in 1816, when he described it in his book Histoire des Polypiers Coralligènes Flexibles, Vulgairement Nommés Zoophytes. He gave the specific epithet "beauvoisii" to honor Palisot de Beauvois, an 18th-century French entomologist and biologist. (the coast of Portugal) by an unknown collector and was donated to the Lamouroux herbarium by de Beauvois, Synonymy While Amphiroa beauvoisii does not have any homotypic synonyms, or officially invalid nomenclature, it does have several illegitimate names. Some of these are simply superfluous, while others are misapplied to A. beauvoisii. In 1824, Lamoroux introduced the named Amphiroa belvisii; however, he discussed A. beauvoisii as a synonym in his description, thus making A. belvisii an illegitimate and superfluous name. A list of heterotypic synonyms according to Adele Harvey et al. in 2009 is as follows: Later studies revealed A. exilis to be a distinct species from A. beauvoisii, with consistent characteristics being observed between the syntype and other Australian specimens of A. exilis. While its own species, A. exilis is still very closely related in appearance to A. beauvoisii. == Distribution, habitat, and ecology ==

Amphiroa beauvoisii is one of the most widely distributed species in the genus Amphiroa, found primarily in tropical and subtropical climates. It has been recorded from the Mediterranean, the Indian Ocean, the Gulf of California, the Caribbean, and the South African coast. More recently, in 2009, it was found in temperate waters along the southwest, south, and southeast Australian coasts. However, it is possible that some of the individuals collected from the southwest coast were actually misidentified A. anceps specimens. The habitat of the species is rocky intertidal pools, and it grows on the surface of rocks. It can be found at depths of up to below the surface of the water. Life cycle Red algae, including A. beauvoisii, exhibit different forms through different generations. This process typically begins as a gametophyte generation, then a sporophyte generation, then a carposporophyte generation which germinates into a tetrasporaphyte. In A. beauvoisii, these different generations will exist in different proportions to one another depending on the geographic location. In subtropical climates, tetrasporangial, bisporangial and gametangial specimens have been found. There are three different proportions found in tropical regions: equal rates of gametangial and sporangial specimens (Pacific Mexico), mostly sporangial specimens (Gulf of California), or only tetrasporangial and bisporangial specimens (Caribbean). In the Australian populations of A. beauvoisii, tetrasporangial forms are common, while gametangial and carposporangial forms have not been recorded. == Research ==

Amphiroa beauvoisii has been tested for bioactive properties, but showed no activity in antibacterial, antifungal, antiviral, cytotoxic, or antimitotic applications. == References ==