Helgi Jónsson

Helgi Jónsson (11 April 1867, Rangárvallasýsla – 1925) was an Icelandic botanist and phycologist.

He specialized in research of marine algae and subarctic vegetation. During his career he undertook many botanical trips throughout Iceland.

• The marine algae of Iceland. Botanisk Tidsskrift 25: 378–380. 1902–1903.
• The marine algae of East Greenland. Meddelelser om Grønland 30: 1-73. 1904.
• The marine algal vegetation of Iceland. The Botany of Iceland, edited by L. Kolderup Rosenvinge & E. Warming, J. Frimodt, Copenhagen, and John Wheldon and Co., London; Vol. 1, Part 1, pp. 1–186. 1912.

The diatom Navicula jonssoniiis named for him.