Heterosiphonia wurdemannii (J. Bailey ex Harvey) Falkenberg var. laxa Børgesen, 1919: 327, figs. 327, 328 (type locality: St. Croix, Virgin Islands).—Børgesen, 1934a: 29 (as forma).— Børgesen, 1934b: 49 (as forma).— Børgesen, 1939b: 133.— S. Dixit, 1966: 21.— Umamaheswara Rao, 1969d: 47.— Gopalakrishnan, 1970: 66.— V. Krishnamurthy & H. Joshi, 1970: 27.— Nizamuddin & Gessner, 1970: 12.— Umamaheswara Rao, 1974e: 65.— Sartoni, 1975: 299.— Sartoni, 1976: 136.
Heterosiphonia crispella (C. Agardh) Wynne var. laxa (Børgesen) Wynne, 1985e: 87.—Wynne, 1993: 15.
INDIAN OCEAN DISTRIBUTION: India, Iran, Maldives, Somalia.