Question: To which taxonomic category do both Wittrockia and Aristotelia belong?

Context paragraphs:
Wittrockia: Wittrockia is a genus of the botanical family Bromeliaceae, subfamily Bromelioideae.

Cladorhiza inversa: 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.

Heterostropha: 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: 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.

Helleborine: 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".

Gammaridae: 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.

Eogastropoda: 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.

Aristotelia (plant): Aristotelia is a genus with 18 species, of tree in the family Elaeocarpaceae.  It is named in honor of the Greek philosopher Aristoteles.

Aptera: Aptera is an obsolete taxonomic category, which included the Apterygota along with various other wingless arthropods.

Sigmurethra: 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.

Supporting paragraphs: Wittrockia Aristotelia (plant)
Answer: genus