sun flower

Description

Through sunflower, pardon? is frequently called the flower is truly a flower head (moreover famous as a complex flower) of various florets, (small flowers) packed mutually. The external petal-bearing florets are the hygienic beam florets and can be yellow, red, orange, or other colors. The florets within the round start are called disc florets, which full-grown interested in seeds.
The florets inside the sunflower's come together are agreed in a spiral pattern. Naturally both floret is tilting just before the after that by around the golden angle, 135.5°, produce a outline of interconnecting spirals somewhere the integer of absent spirals and the integer of correct spirals are following Fibonacci numbers. Naturally, here are 34 spirals in single route and 55 in the extra; on a extremely great sunflower present could be 89 in single course and 144 in the extra. This guide produces the  majority well-organized stuffing of seeds inside the flower top.
Sunflowers the majority usually produce to height among 1.5 and 3.5 m (5–12 ft). Logical literature^[who?] news that a 12 m (40 ft), usual single-head, sunflower stand was full-grown in Padua in 1567. The similar seed batch grow about 7 m (25 ft) at extra period and spaces, with Madrid.^{[citation needed]} Through the 20th century, height of more than 7 m have been achieve in together Netherlands and Ontario, Canada.^{[citation needed]}

 

Heliotropism

Although the ordinary belief^{[by whom?]}, adult sunflowers do not way the sun. The adult flowerheads classically expression east; simply little sunflowers display heliotropism (sun rotary): the trees and buds of little sunflowers trail the sun so that their course change beginning east to west through the way of a daytime.^[7] The actions turn into a circadian answer and after plants are rotate 180 degrees, the mature answer model is at rest follow used for a little days, through side course varying beginning west to east in its place^[8] The side and flowerhead blossom phototropism occur even as the sheet petioles and stem are unmoving vigorously rising excluding one time adult the travels end These travels occupy the petioles winding or parody through the day then fixed or untwisting at dark.^[9]

History

The sunflower is local to Central America. The proof thus distant is that it was primary domesticated in Mesoamerica, near daytime Mexico, in at slightest 2600 BC.^[10] It might have been broken a next instance in the center Mississippi Valley, or been introduce there as of Mexico at an untimely time, as maize was. The first recognized example of a completely broken sunflower north of Mexico have been establish in Tennessee and date to approximately 2300 BC^{[citation needed]}. Many indigenous American peoples used the sunflower as the icon of their solar deity, counting the Aztecs and the Otomi of Mexico and the Incas in South America. Francisco Pizarro was the original European to run into the sunflower in Tahuantinsuy. A few researchers row that the Spaniards try to contain promotion of the sunflower since of its union among astral faith and fighting.^[11]