Lessonia flavicans

{{Short description|Species of seaweed}}

{{Speciesbox

| image =

| image_caption =

| genus = Lessonia (alga)

| species = flavicans

| authority = Bory de Saint-Vincent, 1825

}}

Lessonia flavicans is a species of kelp in the genus Lessonia, native to the shallow seas off the far south of South America and the Falkland Islands.{{cite journal | last1=Nardelli | first1=Allyson E. | last2=Visch | first2=Wouter | last3=Wright | first3=Jeffrey T. | last4=Hurd | first4=Catriona L. | title=Concise review of genus Lessonia Bory | journal=Journal of Applied Phycology | volume=35 | issue=4 | date=2023 | issn=0921-8971 | doi=10.1007/s10811-023-02968-3 | doi-access=free | pages=1485–1498 | url=https://link.springer.com/content/pdf/10.1007/s10811-023-02968-3.pdf | access-date=2025-06-09}} It is the only alga to have the form of a tree, having a stem up to {{cvt|20|cm}} thick and up to {{cvt|3|m}} tall, topped by dichotomous clusters of flaccid fronds each up to a metre long, and bringing the total height to {{cvt|4|m}}.{{cite book | editor= Sir Joseph Hooker | date= 1847 | title= Botany of the Antarctic Voyage - Volume 1 Part 2 - Algae | location= london | publisher= Lovell-Reeve| pages= 457-460 }}{{cite book | last= Fritsch D.Sc. | first= F. E. | date= 1945 | title= Structure and Reproduction of the Algae - Volume 2 | location= Cambridge, England | publisher= Cambridge Univ. Press | page= 204 }}