Question: Which genus of plant has more species, Melasphaerula or Weigela?

full_context: Document 1: Melasphaerula: Melasphaerula is a genus of flowering plants in the family Iridaceae, first described as a genus in 1803. There is only one known species, Melasphaerula graminea, native to Namibia and the Cape Province in South Africa.
Document 2: Wigandia: Wigandia is a genus of flowering plants within the waterleaf subfamily, Hydrophylloideae. They are found mainly in Central America and South America, though one or two species are found as far north as the United States. Some are grown as ornamental plants and will flourish in most Mediterranean or temperate regions. The genus is named for Johann Wigand (ca. 1523-1587), German Lutheran cleric and theologian, and Bishop of Pomesania.
Document 3: Deutzia: Deutzia ( or ) is a genus of about 60 species of flowering plants in the family Hydrangeaceae, native to eastern and central Asia (from the Himalayas east to Japan and the Philippines), and Central America and also Europe. By far the highest species diversity is in China, where 50 species occur.
Document 4: Wisteria: Wisteria (also spelled Wistaria or Wysteria) is a genus of flowering plants in the legume family, Fabaceae (Leguminosae), that includes ten species of woody climbing vines native to the Eastern United States and to China, Korea, and Japan. Some species are popular ornamental plants. An aquatic flowering plant with the common name wisteria or 'water wisteria' is in fact "Hygrophila difformis", in the family Acanthaceae.
Document 5: Ursinia nana: Ursinia nana DC. is a Southern African annual herb belonging to the Daisy family of Asteraceae. It is a pioneer plant of disturbed ground and usually grows to a height of only 30 cm. It flowers throughout the rainy season and, in mild weather with late rains, well into the autumn months. The leaves are deeply laciniate and bunched. In his 1912 contribution to "Botanische Jahrbucher fur Systematik, Pflanzengeschichte und Pflanzengeographie", the enigmatic German botanist Reinhold Conrad Muschler describes "Ursinia engleriana", found near Okahandja in South West Africa, as a new species of African composite. Later this was considered to be the same as "Ursinia nana" described by de Candolle. Muschler praised the species as being extremely ornamental.
Document 6: Weigela: Weigela is a genus of between six and 38 species of deciduous shrubs in the family Caprifoliaceae, growing to 1–5 m (3-15') tall. All are natives of eastern Asia. The genus is named after the German scientist Christian Ehrenfried Weigel.
Document 7: Chaenomeles: Chaenomeles is a genus of three species of deciduous spiny shrubs, usually 1–3 m tall, in the family Rosaceae. They are native to Japan, Korea, China, Bhutan, and Burma. (Burmese: ချဉ်စော်ကား ) These plants are related to the quince ("Cydonia oblonga") and the Chinese quince ("Pseudocydonia sinensis"), differing in the serrated leaves that lack fuzz, and in the flowers, borne in clusters, having deciduous sepals and styles that are connate at the base.
Document 8: Dimorphotheca sinuata: Dimorphotheca sinuata, the glandular Cape marigold, Namaqualand daisy, or orange Namaqualand daisy; syn. "Dimorphotheca aurantiaca" hort.) is an African species of plants native to southern Africa. It is also widely cultivated as an ornamental and naturalized in parts of the United States, primarily California and Arizona.
Document 9: Romulea bulbocodium: Romulea bulbocodium is one of the best-known species from the genus "Romulea". The plant, a member of the Iridaceae family, is native to the Mediterranean region (southern Europe, northern Africa, the Middle East) and Sudan. It has many varieties and is occasionally used as ornamental plant.
Document 10: Sparaxis: Sparaxis (harlequin flower) is a genus in the family Iridaceae with about 13 species endemic to Cape Province, South Africa.
Document 11: Dichroa: Dichroa is a genus of 12 species of flowering plants in the family Hydrangeaceae, native to eastern and southeastern Asia. They are deciduous shrubs growing to 1-3 m tall, with their leaves arranged in opposite pairs. The flowers are produced in a broad inflorescence similar to that of the related genus "Hydrangea". The fruit is a glossy metallic purple-blue berry.
Document 12: Hydrangea: Hydrangea ( ; common names hydrangea or hortensia) is a genus of 70–75 species of flowering plants native to southern and eastern Asia (China, Japan, Korea, the Himalayas, and Indonesia) and the Americas. By far the greatest species diversity is in eastern Asia, notably China, Japan, and Korea. Most are shrubs 1 to 3 meters tall, but some are small trees, and others lianas reaching up to 30 m by climbing up trees. They can be either deciduous or evergreen, though the widely cultivated temperate species are all deciduous.
Document 13: Abelia: Abelia is a genus of about 30 species and many hybrids in the honeysuckle family Caprifoliaceae. Some authors, including the Angiosperm Phylogeny Group, consider "Abelia" and related genera to belong instead in the segregate family Linnaeaceae, also including such genera as "Linnaea", "Abelia", "Dipelta", "Kolkwitzia", and "Zabelia", but not such others as "Lonicera" or "Symphoricarpos," included by them instead in a more narrowly viewed Caprifoliaceae.
Document 14: Sphaeralcea: Sphaeralcea is a genus of flowering plants in the mallow family (Malvaceae). There are about 40-60 species, including annuals, perennials, and shrubs. Most originate in the drier regions of North America, with some known from South America. They are commonly known as globemallows, globe mallows, or falsemallows. The name of the genus is derived from the Greek words σφαῖρα ("sphaira"), meaning "sphere," and αλκεα ("alkea"), meaning "mallow."
Document 15: Romulea: Romulea is a genus of flowering plants in the iris family, first described as a genus in 1772. It is distributed in Europe, the Mediterranean, the Arabian Peninsula, and Africa.
ground_truth: Weigela is a genus of between six and 38 species