Mirabilis jalapa (the four o'clock flower or marvel of Peru) is the most commonly grown ornamental species of Mirabilis, and is available in a range of colours. Mirabilis in Latin means wonderful and Jalapa is a not uncommon placename in Central and North America. Mirabilis jalapa is said to have been exported from the Peruvian Andes in 1540.
Flowers and color
A curious aspect of this plant is that flowers with both different colors can be found simultaneously on the same plant.
Additionally, an individual flower can be splashed with different colors. Flower patterns are referred to as sectors (whole sections of flower), flakes (stripes of varying length), and spots. A single flower can be plain yellow, pink or white, or have a combination of sectors, flakes and stripes. Furthermore, different combinations of flowers and patterns can occur on different flowers of the same plant.  Another interesting point is a color-changing phenomenon. For example, in the yellow variety, as the plant matures, it can display flowers that gradually change to a dark pink color. Similarly white flowers can change to light violet.
The flowers usually open from late afternoon onwards, hence the first of its common names. Flowers then produce a strong, sweet-smelling fragrance throughout the night, then close for good in the morning. New flowers open the following day.
In Pakistan it is called "Gul Adnan" (Urdu: گل عدنان), "Gul-e-Abbas" (Urdu: گل عباس). In Sri Lanka it is called "hendirikka" (හෙන්දිරික්කා). In Southern India it is called "Andhi Mandhaarai" (Tamil: அந்தி மந்தாரை). In Andhra Pradesh it is called "Chandrakantha"(Telugu: చ౦దరకా౦త). In Kerala it is called 'Naalumani poovu' (Malayalam: നാലുമണിപ്പൂ, പതിറ്റടിമുല്ല). In Maharashtra it is called "Gulabakshi" (Marathi: गुलबक्षी). In Assamese it is called 'Godhuli Gopal', 'godhuli' meaning evening. In Bengali it is called "sandhyamaloti" (সন্ধ্যামালতি).In Maithili it is called "sanjhaa phool" as it blooms in evening . In Oriya it is called 'Rangani'. In China it is called the "shower flower" (Chinese: 洗澡花; pinyin: xǐzǎo huā) or "rice boiling flower" (simplified Chinese: 煮饭花; traditional Chinese: 煮飯花; pinyin: zhǔfàn huā) because it is in bloom at the time of these activities. In Hong Kong it is known as "purple jasmine" (紫茉莉). The Turkish name is "akşam sefası", which means "evening pleasure". In The Netherlands and in France the name of the plant is 'Nachtschone' and 'belle de nuit' respectively meaning 'Beauty of the night'. In Persian it is called "Laleh Abbasi" (لاله عباسی). In Japan it is called "Oshiroi-bana", as the white, powdery endosperm inside of mature seeds looks like "Oshiroi", the powder foundation used by Geisha.
Habitat and cultivation
M. jalapa hails from tropical South America, but has become naturalised throughout tropical and warm temperate regions. In cooler temperate regions, it will die back with the first frosts, regrowing in the following spring from the tuberous roots. The plant does best in full sun. It grows to approximately 0.9 m in height. The single-seeded fruits are spherical, wrinkled and black upon maturity (see picture), having started out greenish-yellow. The plant will self-seed, often spreading rapidly if left unchecked in a garden. Some gardeners recommend that the seeds should be soaked before planting, but this is not totally necessary. In North America, the plant perennializes in warm, coastal environments, particularly in USDA Zones 9–10.
Around 1900, Carl Correns used Mirabilis as a model organism for his studies on cytoplasmic inheritance. He used the plant's variegated leaves to prove that certain factors outside the nucleus affected phenotype in a way not explained by Mendel's theories. Correns proposed that leaf color in Mirabilis was passed on via a uniparental mode of inheritance.
Also, when red-flowered plants are crossed with white-flowered plants, pink-flowered offspring, not red, are produced. This is seen as an exception to Mendel's Law of Dominance, because in this case the red and white genes are of equal strength, so neither completely dominates the other. The phenomenon is known as incomplete dominance.
Bioassay-guided fractionation of an organic extract of the cell mass from a manipulated plant cell culture of M. jalapa led to the isolation and subsequent identification of an isoflavone, a roteinoid and a dehydrorotenoid, Two of this compounds are responsible for the antimicrobial activity against Candida albicans.
Bioassay-guided fractionation of the methanolic extract of M. jalapa also led to the isolation of an active polyphenolic amide: N-trans-feruloyl 4′-O-methyldopamine. This compound shows moderate activity as an efflux pump inhibitor against multidrug-resistant Staphylococcus aureus.
The flowers are used in food colouring. The leaves may be eaten cooked as well, but only as an emergency food.
An edible crimson dye is obtained from the flowers to colour cakes and jellies.
In herbal medicine, parts of the plant may be used as a diuretic, purgative, and for vulnerary (wound healing) purposes. The root is believed an aphrodisiac as well as diuretic and purgative. It is used in the treatment of dropsy.
The leaves are used to reduce inflammation. A decoction of them (mashing and boiling) is used to treat abscesses. Leaf juice may be used to treat wounds.
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- New Rotenoids from Roots of Mirabilis jalapa. Wang Yi-Fen, Chen Ji-Jun, Yang Yan, Zheng Yong-Tang, Tang Shao-Zong and Luo Shi-De, Helvetica Chimica Acta, August 2002, Volume 85, Issue 8, pages 2342–2348, doi:10.1002/1522-2675(200208)85:8<2342::AID-HLCA2342>3.0.CO;2-S
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- Growth responses and cadmium accumulation of Mirabilis jalapa L. under interaction between cadmium and phosphorus. Yu Z and Zhou Q, J Hazard Mater., 15 August 2009, volume 167, issues 1-3, pages 38-43, doi:10.1016/j.jhazmat.2008.12.082
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