Question: Which name describes a larger grouping of plants, Xanthorhiza or Melicytus?

Context paragraphs:
Melicytus: Melicytus is a genus of flowering plants in the family Violaceae.  "Hymenanthera" is a synonym.

Xanthorhiza: Xanthorhiza simplicissima (yellowroot) is the only member of the genus Xanthorhiza, and one of very few genera in the family Ranunculaceae with a woody stem (the other notable example being "Clematis").  It is native to the eastern United States from Maine south to northern Florida and west to Ohio and eastern Texas.  It contains the alkaloid berberine, which has a number of traditional and contemporary uses for dyeing and medicine.

Asakusa Shrine: Asakusa Shrine (浅草神社 , Asakusa-jinja ) , also known as Sanja-sama ("Shrine of the Three gods"), is one of the most famous Shinto shrines in Tokyo, Japan.  Located in Asakusa, the shrine honors the three men who founded the Sensō-ji.  Asakusa Shrine is part of a larger grouping of sacred buildings in the area.  It can be found on the east side of the Sensō-ji down a street marked by a large stone "torii".

Long-eared owl: The long-eared owl ("Asio otus"), also known as the northern long-eared owl, is a species of owl which breeds in Europe, Asia, and North America.  This species is a part of the larger grouping of owls known as typical owls, family Strigidae, which contains most species of owl.  The other grouping of owls are the barn owls, family Tytonidae.

Eurasian scops owl: The Eurasian scops owl ("Otus scops"), also known as the European scops owl or just scops owl, is a small owl.  This species is a part of the larger grouping of owls known as typical owls, Strigidae, which contains most species of owl.  The other grouping is the barn owls, Tytonidae.  The scientific name is from the Latin "otus" for an eared owl and Ancient Greek "skopos", "watcher".

Pearl-spotted owlet: The pearl-spotted owlet ("Glaucidium perlatum") is an owl that breeds in Sub-Saharan Africa.  This species is a part of the larger grouping of owls known as typical owls, Strigidae, which contains most species of owl.  The other grouping is the barn owls, Tytonidae.

Unamended Christadelphians: The Unamended Christadelphians are a "fellowship" within the broader Christadelphian movement worldwide, found only in the United States and Canada.  They are, like all Christadelphians, millennialist and non-Trinitarian.  The term "Unamended Christadelphians" is not the formal name of this community but is used informally to identify the grouping since a statement of faith traditionally used by many in this community is the "Unamended Statement of Faith".  Similarly, most of the much larger grouping of "Amended Christadelphians" traditionally use a statement of faith that has been amended and therefore, in North America is known by the prefix "Amended".  Nevertheless, Christadelphians worldwide and both Amended and Unamended Christadelphians in North America share fundamentally the same doctrines, with a few exceptions.

Adenocarcinoma: Adenocarcinoma ( ; plural adenocarcinomas or adenocarcinomata ) is a type of cancerous tumor that can occur in several parts of the body.  It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both.  Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist.  Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma.  Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them.

Chestnut-backed owlet: The chestnut-backed owlet ("Glaucidium castanotum") (often misspelled "Glaucidium castanonotum"), is an owl which is endemic to Sri Lanka.  This species is a part of the larger grouping of owls known as typical owls, Strigidae, which contains most of the smaller owl species.  This species was formerly considered to be a subspecies of the jungle owlet.

Spanish Mustang: The Spanish Mustang is an American horse breed descended from horses brought from Spain during the early conquest of the Americas.  They are classified within the larger grouping of the Colonial Spanish horse, a type that today is rare in Spain.  By the early 20th century, most of the once-vast herds of mustangs that had descended from the Spanish horses had been greatly reduced in size.  Seeing that these horses were on the brink of extinction, some horseman began making efforts to find and preserve the remaining "Spanish Mustangs" drawing stock from feral and Native American herds, as well as ranch stock.  The breed was one of the first to be part of a concerted preservation effort for horses of Spanish phenotype, and a breed registry was founded in 1957.

Supporting paragraphs: Xanthorhiza Melicytus
Answer: Melicytus