Thamnophora mertensii Greville, 1830: xlix (type locality: "ad Novam Hollandiam'').—Sonder, 1848 [1846–1848]: 193.
Thamnocarpus mertensii (Greville) Kützing, 1849: 887.—Kützing, 1866: 19–20, pl. 55: figs. d–h.
Plocamium mertensii (Greville) Harvey, 1849 [1847–1849]: 122.—J. Agardh, 1851 [1851–1863]: 401–402.— Harvey, 1855b: 553.— J. Agardh, 1876: 346–347.— Sonder, 1880: 19.— De Toni, 1900: 599–600.— Lucas, 1909: 35.— V. May, 1965: 372.— Womersley, 1971a: 15, 18, 20, figs. 17–23.— Capon et al., 1984: 537.— Ghisalberti & Jefferies, 1990: 99, table 3.— Huisman & Walker, 1990: 409.— Womersley, 1994: 383.
Plocamium procerum (C. Agardh) Suhr var. mertensii (Greville) Harvey, 1862: expl. pl. CCXXIII: fig. 2.—Harvey, 1863: xxxix.
Nereidea mertensii (Greville) Kuntze, 1891: 907.
Taxonomic synonyms:
* Delesseria plocamium C. Agardh var. procera C. Agardh, 1822 [1822–1823]: 181 (lectotype locality: western Australia fide J. Agardh, 1841: 10–11).—C. Agardh, 1824: 251.
Plocamium procerum (C. Agardh) Suhr, 1834: 726 (excluding record).—Kützing, 1843b: 450.— Harvey, 1849 [1847–1849]: 122.— Kützing, 1849: 886.— J. Agardh, 1851 [1851–1863]: 400–401.— Harvey, 1855b: 553.— Harvey, 1862: pl. CCXXIII.— Harvey, 1863: xxxix.— Kützing, 1866: 19, pl. 54: figs. a–d.— J. Agardh, 1876: 347.— Sonder, 1880: 19.— De Toni & Levi, 1888: 72.— Barton, 1893: 142.— De Toni, 1900: 600–601.— Lucas, 1909: 35.— Mazza, 1921 [1919–1925]: 124–125.
Thamnophora procera (C. Agardh) J. Agardh, 1841: 10–11.
Plocamium procerum (C. Agardh) Suhr var. nidificum Harvey, 1863: xxxix (nomen).
Plocamium nidificum J. Agardh, 1876: 346 (type locality: "Ad Novam Hollandiam'').—Sonder, 1880: 19.— De Toni, 1900: 599.— Lucas, 1909: 35.— De Toni & Forti, 1923: 32, pl. III: figs. 6, 7.— De Toni, 1924: 317.— V. May, 1965: 372.
INDIAN OCEAN DISTRIBUTION: Australia.
Note: The synonymy was proposed by Womersley (1971a: 15, 18, 20).