Question: Which is found in the tropics, Alphitonia or Asystasia?
Context: Alphitonia excelsa, commonly known as the red ash or soap tree, is a species of tree in the Rhamnaceae family.  It is endemic to Australia, being found in New South Wales, Queensland, Northern Territory and the northeastern tip of Western Australia.  It is used in bush regeneration as a pioneer species and for amenity planting. Asystasia mysorensis is an edible plant species in the family Acanthaceae found in Africa.  It is used as a leafy vegetable and for animal fodder. Sankowskya stipularis is a genus and a sole known species of trees found only (endemic) in one locality in the Wet Tropics rainforests of north eastern Queensland, Australia.  The species constitutes part of the plant family Picrodendraceae.  Few botanical collections have ever been made of the trees, from a very restricted area of the Wet Tropics rainforests, hence the species has obtained the conservation status of "endangered" in the legislative regulation of the Queensland Government's "Nature Conservation Act 1992". Gymnostoma is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae.  The species grow naturally in the tropics, including at high altitudes having temperate climates, in forests in the region of the western Pacific ocean and Malesia.  In New Caledonia, published botanical science describes eight species found growing naturally, which botanists have not found anywhere else (endemics).  Additional species have been found across Burma, Sumatra, Borneo, the Philippines, Sulawesi, Ambon Island, the Moluccas, New Guinea, the Bismarck Archipelago, the Solomon Islands, and one endemic species each in Fiji and the Wet Tropics of Queensland, Australia. The genus Asystasia belongs to the family Acanthaceae and comprises approximately 70 species found in the tropics, including the weedy species "Asystasia gangetica". Danis danis, the large green-banded blue, is a species of butterfly in the family Lycaenidae.  This species can be found in the Australia and New Guinea.  Larva feed on "Alphitonia excelsa". Tierra templada (Spanish for "temperate land") is a pseudoclimatological term used in Latin America to refer to places which are either located in the tropics at a moderately high elevation or are marginally outside the astronomical tropics, producing a somewhat cooler overall climate than that found in the tropical lowlands, the zone of which is known as the tierra caliente. The family Melastomataceae (alternatively Melastomaceae) is a taxon of dicotyledonous flowering plants found mostly in the tropics (two thirds of the genera are from the New World tropics) comprising c. 165 genera and c. 5115 known species.  Melastomes are annual or perennial herbs, shrubs, or small trees. Cyclosorus interruptus, the swamp shield-fern, is a fern in the family Thelypteridaceae, that is native to the tropics and subtropics of all the continents.  In the New World, it is found from Mexico to Argentina, and in the Antilles.  In the Old World, it is found in India, China, Malaysia, Sri Lanka and South Africa.  It is also found in Australia, New Zealand, Hawaii and other islands in the Pacific Ocean.  The various populations differ with respect to genetic cytotypes, glands, pubescence, and frond size.  Its habitat is the vicinity of freshwater swamps and it may reach 1 m in height. Alphitonia is a genus of arborescent flowering plants comprising about 20 species, constituting part of the buckthorn family (Rhamnaceae) of the rosid eudicots.  They occur in tropical regions of Southeast Asia, Oceania and Polynesia.  These are large trees or shrubs.  In Australia, they are often called "ash trees" or "sarsaparilla trees".  This is rather misleading however; among the flowering plants, "Alphitonia" is not closely related to the true ash trees ("Fraxinus" of the asterids), and barely at all to the monocot sarsaparilla vines ("Smilax").
Answer: Asystasia