The Key lime or acid lime is a citrus hybrid native to tropical Southeast Asia. It has a spherical fruit, 2.5–5 centimetres in diameter. The Key lime is usually picked while it is still green, but it becomes yellow when ripe.
Key lime
A tree full of key limes in West Bengal, India
Key lime is known as dayap in the Philippines, where it is native
Flowers of the Key lime plant
Citrus taxonomy refers to the botanical classification of the species, varieties, cultivars, and graft hybrids within the genus Citrus and related genera, found in cultivation and in the wild.
Various citrus types in cross section. Some of them are hybrids between two or more original species. The botanical classification of the species, hybrids, varieties and cultivars belonging to the genus Citrus is called "citrus taxonomy".
Mandarin orange is a true species (Citrus reticulata); it is one of the progenitors of most cultivated citrus
The pomelo (Citrus maxima)
These varieties of citron (Citrus medica), Greek and fingered, have distinctly different appearances