Zinnia

Zinnias are annuals, shrubs, and sub-shrubs native primarily to North America, with a few species in South America. Most species have upright stems but some have a lax habit with spreading stems that mound over the surface of the ground. They typically range in height from 10 to 100 cm tall (4" to 40"). The leaves are opposite and usually stalkless (sessile), with a shape ranging from linear to ovate, and a color ranging from pale to medium green. Zinnia's composite flowers consist of ray florets that surround disk florets, which may be a different color than the ray florets and mature from the periphery inward. The flowers have a range of appearances, from a single row of petals to a dome shape. Zinnias may be white, chartreuse, yellow, orange, red, purple, or lilac.. Nectar is secreted at the base of the floret, attracting long‑tongued bees and butterflies. As the style continues to grow, it divides into two branches, with the stigmatic surfaces at the tips maturing to receive pollen. File:ZinniaFloret 10 prob4 62.webm|thumbtime=71|Time-lapse (200×) of Zinnia disc floret petals opening, their styles providing secondary pollen presentation. Visiting insects shown at normal speed. A thrips and two hoverflies eat the piled pollen. Two skipper butterflies reach the deep nectaries. File:Zinnia insect pollenation.webm|thumbtime=152|Time-lapse (200×) of a Zinnia disc floret with stigmas maturing after pollen release. Visiting insects: hoverflies, an immature insect, and skipper butterflies shown at normal speed. Closeup of style and stigmas shown during visits. ==Etymology==

The genus name honors the German scientist Johann Gottfried Zinn (1727–1759), ==Cultivation==

Zinnias are easy to grow with potential heavy, brightly colored blooms. Their petals can take different forms as single row with a visible center (single-flowered zinnia), numerous rows with a center that is not visible (double-flowered) and petals that are somewhere in-between with numerous rows but visible centers (semi-double-flowered zinnia). Their flowers can also take several shapes. Zinnias are an annual plant usually grown in situ from seed. They dislike being transplanted due to having a fragile root system, but can be started indoors 4-6 weeks before planting and moved before their roots fully develop. Much like daisies, zinnias prefer to have full sunlight and adequate water. In the preferred conditions they will grow quickly but are sensitive to frost and therefore will die after the first frost of autumn. Zinnias benefit from deadheading to encourage further blooming. ==Species==

; Accepted species • Zinnia acerosa (syn. pumila) – Arizona, New Mexico, Texas, and Utah in the United States; Coahuila, Durango, Michoacán, Nuevo León, San Luis Potosí, Sonora, and Zacatecas in Mexico. • Zinnia americana – Chiapas, Guerrero, Honduras, Jalisco, Michoacán, México State, Nayarit, Nicaragua, Oaxaca, and Veracruz. • Zinnia angustifolia – Chihuahua, Durango, Jalisco, San Luis Potosí, and Sinaloa. • Zinnia anomala – Texas; Coahuila, and Nuevo León. • Zinnia bicolor – Chihuahua, Durango, Guanajuato, Jalisco, Nayarit, and Sinaloa. • Zinnia citrea – Chihuahua, Coahuila, and San Luis Potosí. • Zinnia coahuilana – Coahuila. • Zinnia elegans – from Jalisco to Paraguay; naturalized in parts of United States. • Zinnia flavicoma – Guerrero, Jalisco, Michoacán, and Oaxaca. • Zinnia grandiflora – Arizona, Colorado, Kansas, New Mexico, Oklahoma, and Texas; Chihuahua, Coahuila, Nuevo León, Sonora, and Tamaulipas. • Zinnia guanajuatensis – Northeast Mexico. • Zinnia haageana – Guanajuato, Jalisco, México State, Michoacán, and Oaxaca. • Zinnia juniperifolia – Coahuila, Nuevo León, and Tamaulipas. • Zinnia maritima (syn. palmeri) – Colima, Guerrero, Jalisco, Nayarit, and Sinaloa. • Zinnia marylandica – Belize • Zinnia microglossa – Guanajuato and Jalisco. • Zinnia oligantha – Coahuila. • Zinnia peruviana (syn. pauciflora) – widespread from Chihuahua to Paraguay including Galápagos and West Indies; naturalized in parts of China, South Africa, and the United States. • Zinnia purpusii – Chiapas, Colima, Guerrero, Jalisco, and Puebla. • Zinnia tenella – Durango. • Zinnia tenuis – Chihuahua. • Zinnia venusta – Guerrero. • Zinnia zamudiana – Querétaro, Hidalgo. • Zinnia zinnioides – Widespread in Mexico. ; Formerly included Hummingbird hawk-moth straw streched.JPG|Hummingbird hawk-moth 'Inachis io' 2.JPG|Aglais io 'Vanessa cardui' 1.JPG|Vanessa cardui 'Admiral - Vanessa atalanta' 01.JPG|Vanessa atalanta 'Aglais urticae' 6.JPG|Aglais urticae Monarch Butterfly Pink Zinnia 1800px.jpg|Monarch butterfly ==Uses==

Zinnias are popular garden flowers because they come in a wide range of flower colors and shapes, and they can withstand hot summer temperatures and are easy to grow from seeds. They bloom all summer long. They are grown in fertile, humus-rich, and well-drained soil, in an area with full sun. They will reseed themselves each year. Over 100 cultivars have been produced since selective breeding started in the 19th century. Zinnia peruviana was introduced to Europe in the early 1700s. Around 1790 Z. elegans (Zinnia violacea) was introduced. Those plants had a single row of ray florets, which were violet. In 1829, scarlet flowering plants were available under the name "Coccinea". Double flowering types were available in 1858, coming from India, and they were in a range of colors, including shades of reds, rose, purple, orange, buff, and rose striped. A number of species of zinnia are popular flowering plants, and interspecific hybrids are becoming more common. ==Cultivation in microgravity==

of the International Space Station, having germinated and grown in microgravity. Zinnias were the first plants grown as part of a formal NASA experiment using the Veggie plant-growth system aboard the International Space Station, helping researchers study how more complex flowering crops could be cultivated in microgravity. ==Companion plants==

In the Americas their ability to attract hummingbirds is also seen as useful as a defense against whiteflies, and therefore zinnias are a desirable companion plant, benefiting plants that are inter-cropped with it. ==Gallery==

File:Zinnia acerosa flowers.jpg|Zinnia acerosa File:Zinnia grandiflora 2.jpg|Zinnia grandiflora File:Starr 030202-0031 Zinnia peruviana.jpg|Zinnia peruviana File:Gol4tara.jpg|Zinnia elegans File:Zinnia angustifolia 'Pette Land White'2.jpg|Zinnia angustifolia File:Zinnia haageana 'Aztec Burgundy Bicolor' kz2.jpg|Zinnia haageana File:Zinnias in Oklahoma.jpg|Zinnia elegans File:Zinnia Flowers in the Garden.jpg|A group of Zinnia flowers == See also ==