Wiktionary
n. (red alga English)
WordNet
n. marine algae in which the chlorophyll is masked by a red or purplish pigment; source of agar and carrageenan
Wikipedia
The red algae, or Rhodophyta ( or ; from Ancient Greek: ῥόδον rhodon, "rose" and φυτόν phyton, "plant"), are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species of mostly multicellular, marine algae, including many notable seaweeds. Other references indicate as many as 10,000 species; more detailed counts indicate about 4,000 in about 600 genera (3,738 marine species in 546 genera in 10 orders, plus the unclassifiable; and 164 freshwater species in 30 genera in eight orders).
The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts that lack external endoplasmic reticulum, contain unstacked thylakoids and use phycobiliproteins as accessory pigments (giving them their red color). They store floridean starch, a type of starch that consists of highly branched amylopectin without amylose, as food reserves outside their plastids. Most red algae are also multicellular, macroscopic, marine, and use sexual reproduction to reproduce. They have alternation of generations and may have three generations rather than two.
The coralline algae, which secrete calcium carbonate and play a major role in building coral reefs, belong here. Red algae such as dulse (Palmaria palmata) and laver ( nori/ gim) are a traditional part of European and Asian cuisines and are used to make other products such as agar, carrageenans and other food additives.
Usage examples of "red algae".
Carpets of red algae, the produce of sewage, fertilizer and effluent from cows, pigs and industrial waste, are, at times, visible along certain parts of the coast, while the dead fish and molluscs, starved by these algae of oxygen, are washed up onto the shore.
Instead, light is gathered by a pigment similar to that of your red algae.
Though the brilliant blues and greens, in trees and rocks alike, punctuated by streaks of brilliant orange-and-red algae and fungi, made for a colorful (if deadly, draining, and inedible) hike.