| Nemastomatales | |
|---|---|
Scientific classification  | |
| (unranked): | Archaeplastida |
| Division: | Rhodophyta |
| Class: | Florideophyceae |
| Subclass: | Rhodymeniophycidae |
| Order: | Nemastomatales Kylin 1925 emend. [1] |
| Families [2] | |
| |
Nemastomatales is an order of red algae. It includes some members of the defunct order Cryptonemiales. [3]
Algae is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella,Prototheca and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 metres (160 ft) in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts.
Brown algae, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Sargassum natans, which is a brown algae, is found in the Sargossa Sea, which lies between the West Indies and the Azores. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food.
Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of red, but some species can be purple, yellow, blue, white, or gray-green. Coralline algae play an important role in the ecology of coral reefs. Sea urchins, parrot fish, and limpets and chitons feed on coralline algae. In the temperate Mediterranean Sea, coralline algae are the main builders of a typical algal reef, the Coralligène ("coralligenous"). Many are typically encrusting and rock-like, found in marine waters all over the world. Only one species lives in freshwater. Unattached specimens may form relatively smooth compact balls to warty or fruticose thalli.
Chordariaceae is a family of brown algae. Members of this family are may be filamentous, crustose with fused cells at the base, or they may be terete and differentiated into a central medulla and an outer photosynthetic cortex. They have a sporphytic thallus usually aggregated to form a pseudo-parenchyma.
The history of phycology is the history of the scientific study of algae. Human interest in plants as food goes back into the origins of the species and knowledge of algae can be traced back more than two thousand years. However, only in the last three hundred years has that knowledge evolved into a rapidly developing science.
Peyssonnelia is a genus of thalloid red alga. It includes the algae commonly known as rumoi-iwanokawa, mayoi-iwanokawa and akase-iwanokawa. Specimens can reach around 20 cm in size. Peyssonnelia produces tetraspores.
The Cryptonemiales is a defunct algal order; it is synonymous with the Halymeniales and has significant overlap with the Nemastomatales.
Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but are relatively rare in freshwaters. Approximately 5% of the red algae occur in freshwater environments with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck where the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.
Rhodomelaceae is estimated to be the largest red algae family, with about 125 genera and over 700 species.
Acrochaetiales is an order of red algae.
Gilbert Morgan Smith was a botanist and phycologist, who worked primarily on the algae. He was best known for his books, particularly the Freshwater Algae of the United States, the Marine Algae of the Monterey Peninsula and the two volumes of Cryptogamic Botany.
Blidingia minima is a species of seaweed in the Kornmanniaceae family. It was described by Johann Kylin in 1947.
Colaconema is a genus of marine red algae.
Batrachospermaceae is a family of fresh water red algae (Rhodophyta). Genera within the Batrachospermaceae generally have a "Lemanea-type" life history with carpospores germinating to produce chantransia. Sporophyte phase with meiosis occurs in an apical cell to produce the gametophyte stage. Pit connections have two pit plug cap layers with the other layer enlarged. This family of freshwater red algae is uniaxial, meaning each filament with a single apical cell. The genera included within Batrachospermaceae are listed in the table below.
Wendy Alison Nelson is a New Zealand marine scientist and world expert in phycology. She is New Zealand's leading authority on seaweeds. Nelson is particularly interested in the biosystematics of seaweeds/macroalgae of New Zealand, with research on floristics, evolution and phylogeny, as well as ecology, and life history studies of marine algae. Recently she has worked on the systematics and biology of red algae including coralline algae, distribution and diversity of seaweeds in harbours and soft sediment habitats, and seaweeds of the Ross Sea and Balleny Islands.
Acrosorium is a genus of marine red algae.
Sporolithon is a genus of red coralline algae in the family Sporolithaceae, in the order Corallinales.
Callithamniaceae is a family of red algae (Rhodophyta) in the order Ceramiales. The family was first described by Friedrich Traugott Kützing in 1843.
Titanophorais a genus of seaweeds belonging to family Schizymeniaceae of the order Nemastomatales.