Gigartina tenera J. Agardh (1841: 18) is the only species originally included in Agardhiella by Schmitz (in Schmitz & Hauptfleisch, 1897d: 371). Taylor (in W.R. Taylor & Rhyne, 1970: 10--14) showed that J. Agardh confused two species under that name, one having a more northerly range than the other. Taylor selected as lectotype a specimen from Puerto Rico that was referable to the southern species, which thus took the name A. tenera. The northern species, which includes the material used by Schmitz in describing Agardhiella, thereby lost its traditional name. Rhabdonia baileyi Harvey ex Kützing (1866: 26, pl. 74: figs. c, d), based on a specimen from Greenport, Long Island, New York, was adopted for the northern species, as A. baileyi (Harvey ex Kützing) W.R. Taylor (in W.R. Taylor & Rhyne, 1970: 13). The southern species was transferred from Agardhiella to Solieria by Wynne & W.R. Taylor (1973: 100), as S. tenera (J. Agardh) Wynne & W.R. Taylor. At the same time, those authors proposed a new genus, Neoagardhiella, to accommodate the northern species.
Concluding that the lectotype specimen chosen by Taylor ``does not conform to the protologue of Gigartina tenera'', Gabrielson (1985: 277) proposed another lectotype specimen, one that ``exhibits the greatest conformity with J. Agardh's original description''. This specimen (no. 34483 in the Agardh Herbarium at LD) bears an inscription that is not completely legible and thus its provenance is uncertain. Unlike the lectotype chosen by Taylor, this specimen is representative of the northern species, which thus regains its traditional generic name, Agardhiella. The earliest available epithet for this species, however, has been shown by Kraft & Wynne (1979) to be provided by Sphaerococcus subulatus C. Agardh (1822 [1822--1823]: 328), yielding the correct name A. subulata (C. Agardh) Kraft & Wynne. The correct name for the southern species is Solieria filiformis (Kützing) Gabrielson (1985: 278), based on Euhymenia filiformis Kützing (1863b: 15) from Antigua Island.
The two competing interpretations of Gigartina tenera increase the uncertainty of the taxonomic placement of the Indian Ocean records of this species.