Thoreales is an order of

red algae Red algae, or Rhodophyta (, ; ), make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest Phylum, phyla of algae, containing over 7,000 recognized species within over 900 Genus, genera amidst ongoing taxon ...

belonging to the class

Florideophyceae Florideophyceae is a class of exclusively multicellular red algae. They were once thought to be the only algae to bear pit connections, but these have since been found in the filamentous stage of the Bangiaceae. They were also thought only to ex ...

. The order consists only one family, Thoreaceae .Hassall, A.H. 1845. A history of the British freshwater algae, including descriptions of the Desmideae and Diatomaceae. With upwards of one hundred plates, illustrating the various species. Vol. I. pp. ��viii, ��462, , err. London, Edinburgh, Paris & Leipzig: S. Highley, H. Baillière; Sunderland & Knox; J.B. Baillière; T.O. Weigel. The

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of ''Thoreaceae'' was circumscribed by Arthur Hill Hassall in A history of the British freshwater algae, including descriptions of the ''Desmideae'' and ''Diatomaceae'' in 1845. The family was originally placed in the Nemaliales order before being transferred to the newly created '' Batrachospermales'' order, before being placed later in ''Thoreales'' order in 2002. After various species of the family were analysed for the sequences of the genes coding for the large subunit of RUBISCO ( rbcL) and the small subunit of rRNA (18S rRNA).

Description

The order is characterized by having freshwater species with multi-axial gametophytes, a uni-axial chantransia stage, and pit plugs with two cap layers, the outer one of which is usually plate-like. It has a multi-axial thalli. They have branched uniseriate filaments as long as long and 0.5 mm in diameter. They have a colourless axis filament with dense photosynthetic lateral branches. They are normally reddish-brown, olive-green, blue-green to nearly black in colour.

Distribution

The family has cosmopolitan distribution. Species from the family are found in tropical and sub-tropical regions or in temperate warm waters. ''Thorea'' is found on several continents (including Australia,P. M. McCarthy and Lyn Jessup and South America), but ''Nemalionopsis'' has been only found in Asia and North America.

Genera

As accepted by AlgaeBase; * '' Nemalionopsis'' - 3 spp. * '' Thorea'' - 13 spp. Former genera;''Polycoma'' and ''Thorella'' , Both accepted as synonyms of ''Thorea'' .

References

{{Authority control Florideophyceae Red algae families