Basionym: Chroococcus turgidus var. subviolaceus Wille in Hedwigia 53: 144. 1913.
Elliptical to irregular colonies, 13.0–48.0 µm diam., 2–4–8–16 celled, rarely more. Sheath firm, hyaline, conspicuous, slightly or non-lamellate, smooth. Cells ellipsoid, hemispherical to polygonal, (6.1)7.2–10.4(17.1) µm diam. Cell content homogeneous to granulated, brown-purple to purple.
Habitat: —Rocks near a waterfall and concrete.
Notes: — Chroococcus turgidus var. subviolaceus Wille (1913: 144) was first found growing on rocks, among Plectonema and Tolypothrix trichomes, in Samoa (Wille 1914). The features differing this variety from C. turgidus (Kützing 1846: 5) Nägeli (1849: 46) are the purple cell content, epiphytic habitat, non-lamellate sheath, and the smaller cell diameter. These characteristics are sufficient to classify Chroococcus turgidus var. subviolaceus as a separate species from C. turgidus. According to the Atlantic Rainforest material, we suspect that C. subviolaceus is very common in tropical terrestrial habitats of humid forests. Komárek & Anagnostidis (1998) considered this variety a synonym of Chroococcus westii Boye-Petersen (1923: 263). However, this species was first described in small Iceland lakes, and besides the habitat, Boye-Petersen (1923) mentioned that C. westii is quite different from C. turgidus var. subviolaceus by its larger cell diameter and by the sheaths being distinctly lamellate. We are not in agreement with the proposal by Komárek & Anagnostidis (1998) and propose the new status of this variety.
Studied material: — BRAZIL. São Paulo: Peruíbe, Ecological Station “Juréia-Itatins”, 24° 23.737’ S, 47° 0.699’ W, 16 August 2011, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427320); 24° 22.694’ S, 47° 4.793’ W, 16 August 2011, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427321); 24° 22.685’ S, 47° 4.797’ W, 16 August 2011, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427322); 24° 23.013’ S, 47° 4.836’ W, 17 August 2011, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427324); 24° 23.708’ S, 47° 7.324’ W, 17 August 2011, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427330); 24° 22.739’ S, 47° 4.719’ W, W.A. Gama-Jr., G.S. Hentschke, C.F.S. Malone & C.L. Sant’Anna (SP 427333).