Müll.Hal.

Johann Karl (or Carl) August (Friedrich Wilhelm) Müller (16 December 1818 – 9 February 1899) was a German bryologist born in Allstedt.

Prior to 1843 he worked as a pharmacist at several locations in Germany (Kranichfeld, Jever, Detmold and Blankenburg am Harz), followed by studies in botany at the University of Halle (1843 to 1846). In 1843 he became an assistant editor of Botanische Zeitung, and in 1852 was co-founder of the journal Die Natur. During his career he amassed a moss herbarium consisting of 12,000 bryological species.Pyrrhobryum parramattense is one of the many species he described.

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