| Johan Johnsen Havaas | |
| Image Upright: | 0.6 |
| Birth Date: | 19 October 1864 |
| Birth Place: | Granvin |
| Death Place: | Voss |
| Nationality: | Norwegian |
| Fields: | Botany |
| Author Abbrev Bot: | Hav. |
Johan Johnsen Havaas (Havås) (19 October 1864–27 April 1956) was a farmer and botanist from Granvin in Hordaland.
Johan Havaas grew up on the farm Havås in Granvin and took an early interest in natural history and botany. He was particularly interested in the cryptogam flora. Havaas had only social studies and was largely self-taught, and also learned foreign languages (including Latin, English, German, French, Portuguese and Spanish) on his own, so he could both exchange letters with scientists abroad and publish his dissertations. With support from the Bergen Museum, among others, he traveled all over the country and collected and recorded large quantities of mosses, lichens and parasitic fungi. His interest was too low, and he himself described about 6 new species. For example, he found the first specimen of the lichen coastal coral lichen (Bunodophoron melanocarpum) in Norway, near Mosterhamn in Sunnhordaland in 1912. In 1911 he registered a find of bog herring (Saxifraga hypnoides) in Stadlandet, a moss that was first found in Norway in the early 1800s. Two lichens have been given a species epithet named after him. One is Flavoplaca havaasii, the other is Umbilicaria havaasii. His work aroused international interest, while he has been less well known in Norway. The Granvin Bygdatun Museum has a collection after Johan Havaas, otherwise there are collections after him at the University of Bergen and at Duke University in North Carolina in the USA. In 1934 he was honored with the King's Medal of Merit in gold. He continued to run his father's farm in Granvin even in his old age. He probably had the last kvanngarden in Granvin.
Johan Havaas has also published two valuable exsiccata works: