Question: Which genus, Callianthemum or Chamaemelum, is native to more continents?
Context: Fimbristylis is a genus of sedges.  A plant in this genus may be known commonly as a fimbry, fimbristyle, or fringe-rush.  There are 200 to 300 species distributed worldwide.  Several continents have native species but many species have been introduced to regions where they are not native.  Some are considered weeds.  These are typical sedges in appearance, with stiff, ridged stems and cone-shaped terminal panicles of spikelets.  They are found in wet environments, and are most diverse in tropical and subtropical regions. Epicauta is a genus of beetles in the blister beetle family, Meloidae.  The genus was first scientifically described in 1834 by Pierre François Marie Auguste Dejean.  "Epicauta" is distributed nearly worldwide, with species native to all continents except Australia.  Surveys have found the genus to be particularly diverse in northern Arizona in the United States.  Few species occur in the Arctic, with none farther north than the southern Northwest Territory of Canada. Dermacentor, also known as the American Levi tick, is a genus of ticks in the family Ixodidae, the hard ticks.  The genus has a cosmopolitan distribution, with native species on all continents except Australia.  Most occur in the Nearctic ecozone. The subfamily Vespinae contains the largest and best-known eusocial wasps, including true hornets (the genus "Vespa"), and the "yellowjackets" (genera "Dolichovespula" and "Vespula").  The remaining genus, "Provespa", is a small, poorly known group of nocturnal wasps from Southeast Asia.  One genus, "Palaeovespa", has been described from the Eocene fossil record, from Colorado.  Collectively, the group can be found on all continents except Antarctica, and several of these wasps are invasive species, introduced beyond their native ranges, and can be major pests. Chamaemelum is a small genus of plants in the daisy family commonly known as chamomiles or dogfennels.  Perhaps the best-known species is Roman chamomile, "Chamaemelum nobile".  These are annual or perennial herbs, rarely exceeding half a meter in height and usually bearing solitary white daisylike flowers with yellow centers.  They are native to Europe but most species can be found scattered in other continents where they have been introduced. Callianthemum is a genus that consists of 24 species of little rhizomatous herbs from high mountains in Europe, Central Asia and East Asia.  The botanical name comes from the Greek, which means beautiful flower.  The plants are low-growing, ornamental perennials and are lovely to rock garden.  Leaves are small and radical.  Flowers are showy daisy-like, 1.5in in diameter, with 5-15 white or rose-color petals and nectaries at the base.  Blooming in spring. A pig is any of the animals in the genus Sus, within the even-toed ungulate family Suidae.  Pigs include the domestic pig and its ancestor, the common Eurasian wild boar ("Sus scrofa"), along with other species; related creatures outside the genus include the peccary, the babirusa, and the warthog.  Pigs, like all suids, are native to the Eurasian and African continents.  Juvenile pigs are known as piglets.  Pigs are highly social and intelligent animals. Anthemis is a genus of aromatic flowering plants in the family Asteraceae, closely related to "Chamaemelum", and like that genus, known by the common name chamomile; some species are also called dog-fennel or mayweed.  "Anthemis" are native to the Mediterranean region and southwest Asia east to Iran.  A number of species have also become naturalized in the United Kingdom and other parts of the world. Halimodendron is a monotypic genus of legume containing the single species Halimodendron halodendron, which is known by several common names, including common salt tree and Russian salt tree.  It is closely related to the genus "Caragana".  It is native to Russia and southern Asia, but it can be found on other continents where it is an introduced species, and one that is often a noxious weed.  This is a deciduous spiny shrub sprawling to a few meters in maximum width and up to three meters tall.  Stems branch from the base and bear clusters of about four leaflets on sharp spurs.  The ends of branches narrow to spines.  Flowers also appear at the ends of spurs in clusters of two to four pink pealike blossoms each one to two centimeters wide.  The fruit is a black woody inflated pod about 2 centimeters long containing legume seeds.  The plant has a deep and wide root system, with the lateral roots sending up new shoots.  In this manner the plant forms extensive thickets.  When introduced to an area of suitable climate, such as California where it is a known weed, it can invade cultivated land and spread relatively quickly.  It is tolerant of saline soils. Zantedeschia is a genus of 8 species of herbaceous, perennial, flowering plants in the family Araceae, native to southern Africa from South Africa north to Malawi.  The genus has been introduced on all continents except Antarctica.  Common names include arum lily for "Z. aethiopica" and calla and calla lily for "Z. elliottiana" and "Z. rehmannii", although members of the genus are neither true lilies of Liliaceae, true "Arums", or true "Callas" (related genera in Araceae).  They are also often confused with "Anthurium".  The colourful flowers and leaves of both species and cultivars are greatly valued and commonly grown as ornamental plants.
Answer: Callianthemum