Comment:
I became interested in Hölzel in the mid-1990s, when I identified him as Else's art-teacher in Dachau from mirror-image descriptions in her Autobiography [written in Berlin, ca. 1924], and Felix Paul Greve's first novel about her [Fanny Essler, 1905]. -- See the Dachau Registration under her maifen-name in May 1900:

21. V. 1900 - Ploetz, Else Kunststudentin - Swinemünde - geb. 12. Juli 1875

Hölzel started with abstract landscapes and paintings in 1901, years before Kandinsky, who also lived in Munich and nearby Murnau at the time. At first, he used a rather muted palette, later, the vibrant colours as in the pastel shown here.
Sources:
Image adapted from: Ketterer Kunst/Art (Munich, Hamburg, Berlin);
orig. Pastel, 32.5 x 51 cm.
Adolf Hölzel (1853-1934): " ... an artist & art-teacher in Dachau & Stuttgart, who, as early as 1901, became an early promoter of Abstractionism" [see wikipedia entry]