Helleborine is the common name for a number of species of orchid.
 It does not correspond to any currently used taxonomic category.
 Some of the plants called helleborines are classified in the genus "Epipactis", some in genus "Cephalanthera".
 A genus "Helleborine" was formerly recognised but has now been absorbed into the Grass pink genus "Calapogon".
Cladorhiza inversa is a species of sponge in the taxonomic category of Demospongiae.
 The body of the sponge consists of a spicule and fibers and is water absorbent.
Olsynium (huilmo in Chile; formerly part of "Sisyrinchium") is a genus of summer-dormant rhizomatous perennials in the iris family, native to sunny hillsides in South America and western North America.
Eogastropoda was a previously used taxonomic category of snails or gastropods, a subclass which was erected by Ponder and Lindberg in 1997.
 It was one of two great divisions (subclasses) of the class Gastropoda, the snails.
 The other subclass of gastropods was the Orthogastropoda.
Aptera is an obsolete taxonomic category, which included the Apterygota along with various other wingless arthropods.
Heterostropha was a previously used taxonomic category, an order of sea snails, within the superorder Heterobranchia.
 In the most current gastropod taxonomy, that of Bouchet & Rocroi, this taxon is no longer in use.
Cladorhiza segonzaci is a species of sponge in the taxonomic category of Demospongiae.
 The body of the sponge consists of a spicule and fibers and is water absorbent.
Gammaridae is a family of amphipods.
 In North America they are included among the folk taxonomic category of "scuds", and otherwise gammarids is usually used as a common name.
Swainsona is a large genus of flowering plants native to Australasia.
 There are 85 species, all but one of which is endemic to Australia; the exception, "S. novae-zelandiae", occurs only in New Zealand.
Sigmurethra is a taxonomic category of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs.
 This is an informal group which includes the majority of land snails and slugs.

Question: To which taxonomic category do both Swainsona and Olsynium belong?
Answer: genus