Orange — An orange—specifically, the sweet orange—is the citrus tree Citrus sinensis (syn. Citrus aurantium L. var. dulcis L., or Citrus aurantium Risso) and its fruit. The orange is a hybrid of ancient cultivated origin, possibly between pomelo (Citrus maxima) and tangerine (Citrus reticulata). It is a small flowering tree growing to about 10 m tall with evergreen leaves, which …

Onion — Many plants in the genus Allium are known by the common name onion but, used without qualifiers, it usually refers to Allium cepa. Allium cepa is also known as the ‘garden onion’ or ‘bulb’ onion and ‘shallot’. Onions, as one of the oldest vegetables known to mankind are to be found as an ingredient in a bewildering array …

Olive — The Olive (Olea europaea) is a species of small tree in the family Oleaceae, native to coastal areas of the eastern Mediterranean region, from Syria and the maritime parts of Asia Minor and northern Iran at the south end of the Caspian Sea. Its fruit, the olive, is of major agricultural importance in the Mediterranean region as the …

Oleander — Oleander (Nerium oleander), is a evergreen shrub or small tree in the dogbane family Apocynaceae. It is the only species currently classified in the genus Nerium. Other names include Adelfa, Alheli Extranjero, Baladre, Espirradeira, Flor de São Jose, Laurel de jardín, Laurel rosa, Laurier rose, Flourier rose, Olean, Aiwa, Rosa Francesca, Rosa Laurel, and Rose-bay (Inchem 2005), Araliya …

Okra — Okra, also known as lady’s finger, vendaikai (Tamil), bhindi (Hindustani), ramtoriyan (Nepali) and gumbo, is a flowering plant in the mallow (along with such species as cotton and cocoa) family valued for its edible green fruits. Its scientific name is Abelmoschus esculentus. The species is an annual or perennial, growing to 2 m tall. The leaves are 10–20 …

Oat — The common oat plant (Avena sativa) is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other grains). While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed. Oats make up a large part …

Oak, White — The tree species Quercus alba is also called “white oak”. It is a long-lived oak in the family Fagaceae, native to eastern North America, from southern Quebec west to eastern Minnesota, and south to northern Florida and eastern Texas. Specimens are known to have lived over 600 years. Although called the white oak it is very unusual …

Oak, Red — The Northern Red Oak or Champion Oak, Quercus rubra (syn. Quercus borealis), is an oak in the red oak group (Quercus section Lobatae). It is a native of North America, in the northeastern United States and southeast Canada. It grows from the north end of the Great Lakes, east to Nova Scotia, south as far as Georgia …

Nutmeg — The nutmegs Myristica are a genus of evergreen trees indigenous to tropical southeast Asia and Australasia. They are important for two spices derived from the fruit, nutmeg and mace. Nutmeg is the actual seed of the tree, roughly egg-shaped and about 1 inch (20–30 mm) long and 3/4 inch (15–18 mm) wide, and weighing between one quarter and …

Nasturtium — Nasturtium (literally “nose-twister” or “nose-tweaker”), as a common name, refers to a genus of roughly 80 species of annual and perennial herbaceous flowering plants Tropaeolum (“Trophy”), one of three genera in the family Tropaeolaceae. It should not be confused with the Watercresses of the genus Nasturtium, of the Mustard family. This genus, native to South and Central America, …