A geniculate habit, with reference to the red algae, is one in which the alga branches, tree-like, forming "fronds" that attach to the substrate with a holdfast. Non-calcified "genicula" serve as "knees" or hinges between the calcified intergenicula. The geniculate or non-geniculate form of algae was used to classify them; however either form has been convergently derived many times. The genuculae sometimes contain lignin.[1]

Genucila have probably evolved at least three times, evidenced by the three different modes of their formation.[2]

References

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  1. ^ Martone, P.; Estevez, J.; Lu, F.; Ruel, K.; Denny, M.; Somerville, C.; Ralph, J. (2009). "Discovery of Lignin in Seaweed Reveals Convergent Evolution of Cell-Wall Architecture". Current Biology. 19 (2): 169–175. doi:10.1016/j.cub.2008.12.031. PMID 19167225.
  2. ^ Johansen, H. W. (1969). "Patterns of Genicular Development in Amphiroa (Corallinaceae)". Journal of Phycology. 5 (2): 118. doi:10.1111/j.1529-8817.1969.tb02589.x.