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The Chlorophyta Phylum

Part 6: Fan & Finger Macroalgae Species

By Stan & Debbie Hauter, About.com

There are several varieties of green Fan and Finger macroalgae, with most fan species being commonly referred to as Mermaid's Fans. The Udotea and Anadyomene species are Fans, Avrainvillea has various Fans and one Finger species, with Neomeris and Codium being considered Fingers.

The beginning taxonomy line of these alga species goes as follows - Kingdom: Plantae, Algae, or Protista --> Phylum: Chlorophyta (or Chlorophycota) --> Class/Division: Chlorophyceae --> and after this many of the species fall into the same Order --] Family, while some of the others branch off into different Orders and Family classifications all together. Although understanding the taxonomy can sometimes be confusing, they are all still classified into the Chlorophyta Phylum, or green algae group. Let's take a closer look at some of the more common Fan and Finger species named above.

-->Order: Caulerpales
---->Family: Udoteaceae
------> Genus: Udotea
-------->Species: conglutinata, cyathiformis, flabellum, occidentalis, orientalis, wilsonii, & others.

The Udotea species are calcareous fans, meaning they are composed of or contain calcium carbonate, calcium, or limestone. Because they are found in the same Family Udoteaceae as Halimeda sp., this makes them closely related and they can be treated in the same manner.

The calcium content within Udotea gives them a hard fan with varying textured plates, and the plates often have lines of calcium carbonate deposits centered around the middle. Udotea usually anchor into sandy or muddy silt bottoms with a holdfast stemming from or around a single stalk. Their fan plates grow in various shapes, such as in a cup form like that of U. cyathiformis, or in clusters. These species grow from shallow grass flats to deeper depths of 50 feet or more, reaching three to eight inches in height.

Did you know that Parrotfish graze on Udotea and by doing so are important major contributors of marine sediments, or what we all know as beach sand?

--> Genus: Avrainvillea
---->Species: amadelpha, asarifolia, canariensis, eliottii, levis, longicaulis, rawsonii, nigricans, & others.

Avrainvillea species are also found in the Order Caulerpales --> Family Udoteaceae, but are soft, unlike their harder calcifying Udotea and Halimeda relatives. Avrainvillea are blackish-green or dark olive-brown in color and are covered with very fine filaments which gives them a soft surface, similar to the feel of suede or a woolly, felt-like texture. They grow preferably in silty sand and anchor by means of a holdfast that looks like a massive ball of filamentous roots.

A. rawsonii is the only Finger shaped species in this group and grows in grass flat areas, while all the others are Fan shaped and grow from shallow water mangrove areas to mid-water grass flats and out to deeper waters. A. nigricans and A. longicaulis can reach to eight inches in height and four inches in width, but A. nigricans has irregularly shaped jagged-edged fans, while A. longicaulis has more evenly outlined fans. The Hawaiian species A. amadelpha has irregularly shaped fans with smooth edges described as torn paddles. A. elliottii is a shorter species with straighter edged fans, and A. asarifolia has a dinner plate shaped fan that reaches to a height of one foot that surrounds a small stalk.

-->Order: Cladophorales
---->Family: Anadyomenaceae
------> Genus: Anadyomene
-------->Species: stellata, saldanhae, & others.

Next Page > Fan & Finger Macroalgae Species - Page 2

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