title: Polyides rotunda
text: # Polyides rotunda
  
  Polyides rotunda is a species of small red marine alga in the family Polyidaceae.
  
  ## Description
  
  Polyides rotunda grows to 20 cm (7.9 in) in length, its cartilaginous, terete and branches two or three times dichotomously. The branches are about 2 mm (0.079 in) in diameter reaching a uniform height. The holdfast is disc like. In colour it is purplish red.
  
  ## Habitat
  
  Generally epilithic in rock pools in the littoral and upper sublittoral. Sand tolerant.
  
  ## Distribution
  
  Generally distributed around Ireland, Great Britain, the Isle of Man and the Channel Islands.
  
  ## Reproduction
  
  Polyides rotunda is dioecious. The spermatangial cells develop in swollen areas near the apices. Cystocarps develop near the apices. The tetrasporangia are cruciate, that is cross-shaped.
  
  ## Similar species
  
  Furcellaria lumbricalis (Hudson) Lamouroux is very similar but can be distinguished by the holdfast which has claw-like branches while that of Polyides being disc-like.
  
  