Mirabilis jalapa

From Wikipedia, the free encyclopedia

Mirabilis jalapa
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Caryophyllales Family: Nyctaginaceae Genus: Mirabilis Species: M. jalapa
Binomial name
Mirabilis jalapa

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 town in Mexico. Mirabilis jalapa is said to have been exported from the Peruvian Andes in 1540.

[edit] Flowers and colour

A curious aspect of this plant is that flowers of different colours can be found simultaneously on the same plant. Additionally, an individual flower can be splashed with different colours. Another interesting point is a colour-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, then producing a strong, sweet-smelling fragrance, hence the first of its common names. In China, it is called the "shower flower" (Chinese: 洗澡花; pinyin: xǐzǎo huā) or "rice boiling flower" (煮饭花; 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). Despite their appearance, the flowers are not formed from petals – rather they are a pigmented modification of the calyx.

The flowers are pollinated by long-tongued sphynx moths.

[edit] 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 fruit 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 US Zones 9–10.

[edit] Genetic studies

Carl Correns used the four o'clock 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.

Also, when red-flowered plants are crossed with white-flowered plants, pink-flowered offspring, not red, are produced. This is an exception to Mendel's Law of Dominance.