Otto Rudolf Holmberg (1 February 1874, Simrishamn – 28 December 1930) was a Swedish botanist.
Beginning in 1893, he received his education in Lund, where from 1909 onward, he served as curator of the botanical institute.
[1][2] His main written work was "Skandinaviens flora", published in four parts from 1922 to 1931.
[3] Its second volume contained Hampus Wilhelm Arnell's treatise on mosses and liverworts, titled "Mossor a.
[4][5] As a taxonomist, he circumscribed a number of species within the grass genus Puccinellia.