East Arabian fog shrublands and sand desert

The premier true mahogany and one of the most commercially important tropical hardwoods on Earth: a very large neotropical timber tree that reaches roughly 100 to 150 feet with a broad, spreading, rounded crown, pinnately compound leaves, and reddish-brown heartwood prized for fine furniture and instruments. Honesty first: this is a knowledge and conservation entry, not a plant most people can or should grow. It is a frost-tender tropical giant hardy only in USDA zones 10b-12b, native to the neotropics from southern Mexico through Central America into Amazonian South America, with no role as a temperate-garden ornamental. More important than any landscape use is its conservation status - decades of overharvest for that famous mahogany timber have made it conservation-sensitive, and it is listed on CITES Appendix II, meaning international trade is regulated to keep harvest from driving the species toward extinction. Include it for its story and its scale, and source any wood or plant material only through legal, certified, sustainable channels.

The true Christmas cactus - the hybrid Schlumbergera x buckleyi - a long-lived epiphytic holiday cactus grown indoors almost everywhere for its arching, segmented stems and its rose-to-magenta flowers that open in mid-winter, around Christmas. It is worth getting the identity right, because most plants sold and labeled as 'Christmas cactus' are actually the Thanksgiving cactus, Schlumbergera truncata. You can tell the two apart by the edges of the flat stem segments and by when they bloom: the true Christmas cactus has rounded, scalloped segment margins and flowers a few weeks later, in mid-winter, while the Thanksgiving cactus has sharp, claw-like teeth and blooms from late fall into early winter. Unlike a desert cactus, this is a forest epiphyte that grows on tree branches in the Atlantic coastal forest of southeastern Brazil, so it wants bright indirect light, a free-draining mix, sparing water, and - to set its buds - cool nights and short days. A reassuring point that sets it apart from many houseplants: it is non-toxic to cats and dogs. One more field mark clinches it: the true Christmas cactus has rose-pink pollen and flowers that hang almost regularly (radially), where the Thanksgiving cactus has yellow pollen and asymmetric blooms held out nearly horizontally.

A warm-season member of the nightshade family (Solanaceae) - a relative of tomato, potato, and pepper - grown for its showy, glossy edible berries that range from white and green through deep purple to nearly black depending on cultivar. The plant is technically a tender herbaceous perennial but is grown as an annual vegetable across most of North America, where it demands a long, hot, frost-free season to fruit well. Drooping violet star-shaped flowers give way to the familiar pendant fruit; the leaves, flowers, stems, and roots are toxic and only the fruit is eaten.

A vigorous tropical climbing and trailing vine grown almost everywhere as an easy-care houseplant, prized for glossy, heart-shaped leaves marbled and streaked with golden-yellow variegation. In the tropics it scrambles up tree trunks by aerial roots and can climb 13 to 40 feet, with juvenile leaves enlarging dramatically as it ascends; indoors, kept in a pot or trailing from a shelf, it stays only inches tall and a few feet long. It tolerates low light and infrequent watering better than almost any other foliage plant, which is why it is a beginner favorite. Native to the Society Islands of French Polynesia and now naturalized across the tropics, it is hardy outdoors only in frost-free climates (roughly USDA 10b-12b) and is an aggressive invasive weed where it escapes. All parts are toxic if chewed or eaten.

A fast, twining annual vine from tropical America grown for the azure-blue trumpets that open at dawn and fade by afternoon, each marked with a white-to-golden-yellow star throat. Heart-shaped leaves clothe stems that climb 8 to 10 feet in a single season on any support. Showy and easy from seed, but every part - especially the seed - is poisonous if eaten, so site it away from where pets and children graze.

A bold tropical fig from South and Southeast Asia grown almost everywhere as a houseplant for its large, glossy, leathery, deep-green (or cream- and burgundy-variegated) paddle leaves. Honesty first: in its frost-free native habitat and outdoors in USDA zones 9-12 this is a massive strangler-type fig that can reach 50 to 100 feet with a spreading, aerial-rooting crown - but in the homes, offices, and patio containers where almost everyone grows it, it is kept a fraction of that size by pot confinement and pruning. It is easygoing in bright indirect light and forgiving of average indoor conditions; the one real catch is its milky latex sap, a mild skin, eye, and digestive irritant that also bothers latex-sensitive people. The same latex was historically tapped to make natural rubber, which is where the name comes from.

A large, spreading tropical tree from sub-Saharan Africa, famous for the enormous grey, sausage-shaped fruits that dangle on long cord-like stalks beneath its rounded crown. Honesty first: where it is hardy (USDA zones 10a-12b) it grows into a 30-60 foot evergreen-to-semi-deciduous shade tree, and at night it opens large, maroon, foul-smelling, cup-shaped flowers that are pollinated by bats. The fruits are the headline and the hazard - they can reach about 24 inches long and weigh several pounds, and a falling fruit can genuinely injure a person or dent a car, so it must never be sited over patios, walks, or parking. The raw fruit is toxic and purgative to humans; it is used only after careful processing in traditional medicine and skincare, never eaten raw. It is frost-tender and strictly a warm-climate specimen tree, not a temperate-garden plant.

A near-indestructible architectural houseplant grown for stiff, upright, sword-shaped, succulent leaves banded in grey-green - yellow-margined in the popular "Laurentii" - and long known as the snake plant or "mother-in-law's tongue". POWO records it as native to tropical West Africa, and its currently accepted botanical name is Dracaena trifasciata (it was reclassified out of Sansevieria), though the nursery trade and most gardeners still know it as Sansevieria. It is famously tough: it tolerates low light, deep shade to bright indirect light, neglect, and irregular watering, which makes it one of the most forgiving plants you can grow indoors. HONESTY: the commonest way to kill it is OVERwatering - soggy soil rots the rhizome - so the real skill is letting the mix dry out between waterings, not watering more. It is toxic to cats and dogs (saponins cause vomiting and diarrhoea if eaten), and the popular "releases oxygen at night and purifies the air" reputation is overstated at realistic room densities. RHS treats it as a tender houseplant (H1B), frost-tender and grown under glass or indoors except in frost-free climates.

A large tropical evergreen tree from Asia and northern Australia, where it can reach 30 feet or more with a broad, rounded crown of arching, weeping branches clothed in glossy, pointed, 2-4 inch leaves. Across most of the world, though, it is grown as one of the most popular indoor trees, kept to 5 to 10 feet in a pot and valued for its graceful weeping form and dense, shiny foliage. It is hardy outdoors only in frost-free climates (USDA 10a-12b); everywhere colder it is a houseplant. Its single most famous trait is dropping its leaves dramatically whenever it is moved, drafted, over- or under-watered, or otherwise stressed - a habit new owners often mistake for death. The milky white latex in its stems and leaves is mildly toxic if eaten and is a well-known skin and airborne allergen.

The ZZ plant (Zamioculcas zamiifolia) is a glossy, architectural houseplant grown almost everywhere indoors: upright stems carry ranks of dark-green, waxy, pinnate leaflets rising from a thick, water-storing rhizome, and it is among the toughest, most drought-tolerant houseplants there is. POWO (Kew) gives its native range as eastern Africa, from Kenya south to South Africa, where it is the only species in its genus; worldwide it is prized as a near-indestructible foliage plant that thrives on neglect and low light. RHS gives it the Award of Garden Merit as an easy, drought-tolerant tender houseplant and rates it frost-tender (H1B, under glass / indoors), so outside USDA zones 10a-12 it is a year-round indoor plant. Because it stores water in its rhizome, the main way to kill it is OVERwatering, which rots the rhizome; it is slow-growing and rarely needs repotting. Be clear-eyed about the cautions: it is toxic to cats, dogs, and people if chewed (insoluble calcium-oxalate crystals), the sap can irritate skin, so wear gloves when handling or dividing it and keep it away from pets, and its much-repeated air-purifying reputation, which traces to a 1989 NASA sealed-chamber study, is overstated and negligible at realistic room densities.

A clumping, multi-stemmed evergreen perennial from South Africa, grown for its unmistakable crane-head flowers - a horizontal green-and-pink spathe from which bright orange sepals and vivid blue petals emerge like the crest of an exotic bird. Bold, paddle-shaped blue-green leaves on long stalks form a 3-4 foot fountain of foliage. Winter hardy only in USDA zones 10-12 (frost-free subtropics); everywhere colder it is grown as a houseplant or summered-out container plant. It blooms reliably only from a well-established, somewhat crowded clump, so patience is the key to flowers.

The classic florists' gloxinia, a tuberous tropical perennial of the Gesneriaceae native to the Atlantic Forest of south-eastern Brazil (POWO, Kew; recorded as Brazilian-native in Flora e Funga do Brasil). It forms a low, neat rosette of soft, velvety leaves above which sit large, showy, bell-shaped flowers in rich violet, red, pink or white, often finished with a contrasting picotee edge. POWO and Flora e Funga do Brasil record Sinningia speciosa as the wild parent of the cultivated florist gloxinia, and that ornamental heritage is exactly how it is grown almost everywhere - as a tender pot or houseplant prized for its plush leaves and velvety trumpet-and-bell flowers. HONESTY: it is very frost-tender, hardy in the ground only in roughly USDA zone 11 and above, and it has a real dormant season - after flowering it dies back to a resting tuber before regrowing, so it is not an evergreen plant but a cyclical one. It is grown purely as an ornamental: no part is eaten. The flowers are insect-pollinated and, in the plant's native Brazilian range, also visited by hummingbirds.