Question:  Which species, Cardwellia or Ochagavia, is native to South America?

Context paragraphs:
Cardwellia: Cardwellia is a genus of a sole described species of large trees, constituting a part of the plant family Proteaceae.  The species Cardwellia sublimis (northern silky oak) grows naturally only (endemic) in the rainforests of the wet tropics region of north eastern Queensland, Australia.  Other common names include bull oak, golden spanglewood, lacewood, oak and oongaary.  The compound leaves have up to 17 leaflets.  It produces white inflorescences followed by woody fruits which are prominently displayed outside the canopy.

Twist-necked turtle: The twist-necked turtle, "Platemys platycephala", also known as the flat-headed turtle, is distributed widely across northern South America.  Twist-necked turtles have extremely flat shells that help them hide from predators under rocks and debris.  When threatened, this turtle withdraws by twisting its head into its shell.  "P. platycephala" is the only species of the genus "Platemys" and occurs in northern and central South America.  "Platemys platycephala" means “flat turtle, flat-head” and accurately describes the structure of the head and shell.  This species inhabits shallow creek beds and frequently forages on the floor of the Amazon rainforest for insects, amphibians, and mollusks.  Camouflage, head and body shape, and advanced sexual anatomy allow this species of turtle to effectively populate much of South America.  Mating occurs during rainy months (March–December) and egg deposit occurs during dry months (January–March).  Males have been known to behave aggressively towards females during copulation by squirting water from nostrils and biting.  A few genomic studies show mosaicism exists among populations of the twist-necked turtle in Surinam.  In other words, diploid and triploid levels exist among individuals at this particular location.  No threats have been reported for this species and the International Union for Conservation of Nature does not have a current listing.  Lack of human consumption due to the species' small size and its wide range explain why scientists are not concerned about this turtle species.

Alternanthera philoxeroides: Alternanthera philoxeroides, commonly referred to as alligator weed, is a native species to the temperate regions of South America, which includes Argentina, Brazil, Paraguay and Uruguay.  Argentina alone, hosts around 27 species that fall within the range of the genus Alternanthera.  Its geographic range once used to cover only the Parana River region of South America, but it has since expanded to cover over 30 countries, such as the United States, New Zealand, China and many more.  This invasive species is believed to have been accidentally introduced to these non-native regions through sediments trapped/attached to tanks and cargo of ships travelling from South America to these various areas.

List of South American mammals: This is a list of the native wild mammal species recorded in South America.  South America's terrestrial mammals fall into three distinct groups.  The marsupials and xenarthrans are 'old-timers', their ancestors having been present on the continent since at least the very early Cenozoic Era.  During the early Cenozoic, South America's only land connection was to Antarctica, so it was effectively cut off from most of the world; as the fragments of Gondwana continued to separate, this connection was lost, leaving South America an island continent.  Caviomorph rodents and monkeys arrived as 'waif dispersers' by rafting across the Atlantic from Africa in the Eocene epoch, 35 million or more years ago.  All the remaining nonflying mammals of South America are recent arrivals, having migrated from North America via Central America during the past seven million years as part of the Great American Interchange; this invasion, which peaked around three million years ago, was made possible when the formation of the volcanic Isthmus of Panama bridged North and South America.  The newcomers out-competed and drove to extinction many unique mammals that had evolved during South America's long period of isolation, as well as some species from other classes (e.g., terror birds).

Nops (spider): Nops is a genus of medium-sized caponiid spider native to South America, Central America, and the Caribbean islands.  The genus currently counts 27 extant species plus one fossil in Dominican amber, but probably the real number of extant species is greater.  "Nops" have a great richness on the Caribbean islands (14 species).  Even species of Central America (4) and South America (15) are located in high proportion toward the area of the Caribbean Sea.  Most species of South America are known only from the coast of Colombia and Venezuela, including the islands of Aruba, Curaçao, Bonaire and Trinidad.  The genus is not revised yet, but apparently have a Neotropical distribution.

List of mammals of Mexico: This is a list of the native wild mammal species recorded in Mexico.  As of September 2014, there were 536 mammalian species or subspecies listed.  Based on IUCN data, Mexico has 23% more noncetacean mammal species than the U.S. and Canada combined in an area only 10% as large, or a species density over 12 times that of its northern neighbors.  Mexico's high mammal biodiversity is in part a reflection of the wide array of biomes present over its latitudinal, climatic and altitudinal ranges, from lowland tropical rainforest to temperate desert to montane forest to alpine tundra.  The general increase in terrestrial biodiversity moving towards the equator is another important factor in the comparison.  Mexico includes much of the Mesoamerican and Madrean pine-oak woodlands biodiversity hotspots. From a biogeographic standpoint, most of Mexico is linked to the rest of North America as part of the Nearctic ecozone.  However, the lowlands of southern Mexico are linked with Central America and South America as part of the Neotropic ecozone.  Extensive mixing of Nearctic and Neotropical mammal species commenced only three million years ago, when the formation of the Isthmus of Panama ended South America's long period of isolation and precipitated the Great American Interchange.  Twenty of Mexico's extant nonflying species (opossums, armadillos, anteaters, monkeys and caviomorph rodents) are of South American origin.  Most of the megafauna that formerly inhabited the region became extinct at the end of the Pleistocene about 10,000 years ago, shortly after the arrival of the first humans.  Increasing alteration and destruction of natural habitats by expanding human populations during the last several centuries is causing further attrition of the region's biodiversity, as exemplified by the 'hotspot' designations (by definition, such areas have lost over 70% of their primary vegetation).

Invasive species in South America: Invasive species are a serious threat to the native biodiversity of South America and are an ongoing cost to South American agriculture.  South America is an important region for the worlds biodiversity, and includes a wide variety of native species, many of which provide .  Introduced species in South America, have the potential to pose harm to ecosystems of the region and the aforementioned biodiversity.  Although many of these non-native species are invasive, residents of the region often value these species, making it more difficult to organize efforts to get rid of them.  Because of the instrumental and cultural value placed on these species, greater awareness, research, and policy are all necessary steps in solving invasive issues in South America.  Here is a list of just a few of the species that have invaded South America and where they originate.

Galictis: A grison, also known as a South American wolverine, is any mustelid in the genus Galictis.  Native to Central and South America, the genus contains two extant species: the greater grison ("Galictis vittata"), which is found widely in South America, through Central America to southern Mexico; and the lesser grison ("Galictis cuja"), which is restricted to the southern half of South America.  In Spanish it is referred to as a "huroncito" (literally "little ferret") or "grisón" and in Portuguese as a "furão".

Arachis: Arachis is a genus of about 70 species of annual and perennial flowering plants in the pea family (Fabaceae), native to South America, and was recently assigned to the informal monophyletic "Pterocarpus" clade of the Dalbergieae.  At least one species, the peanut ("Arachis hypogaea"), is a major food crop species of global importance; some of the other species are cultivated for food to a small extent in South America.  Other species such as "A. pintoi" are cultivated worldwide as forage and soil conditioner plants, with the leaves providing high-protein feed for grazing livestock and a nitrogen source in agroforestry and permaculture systems.

Ochagavia: Ochagavia is a genus of the botanical family Bromeliaceae, subfamily Bromelioideae.  The genus is named for Sylvestris Ochagavia, Chilean minister of education.  Endemic to southern and central Chile (including the Juan Fernández Islands), this genus is represented by four accepted species.

Supporting paragraphs: Cardwellia Ochagavia
Answer: Ochagavia