Tulip

Tulips belong to the genus *Tulipa* and are spring-blooming, bulb-forming perennials. They are part of the lily family, Liliaceae, and are most closely related to the genera *Amana*, *Erythronium*, and *Gagea* within the tribe Lilieae. The flowers are typically large, showy, and brightly colored—most often red, orange, pink, yellow, or white—and frequently feature a differently colored blotch at the inner base of the tepals. Because of natural variation within populations and a long history of cultivation, classifying tulips has been a complex and debated task. Roughly 75 species exist, split into four subgenera.

The name "tulip" likely comes from a Turkish word for turban, which the flower may have reminded early observers of. In the wild, tulips originally stretched from Southern Europe through Central Asia, thriving in steppes and mountainous areas with temperate climates. They bloom in spring, then go dormant in summer after their flowers and leaves die back, re-emerging from an underground bulb in early spring. Since the 1600s, they have become widely naturalized and cultivated around the world.

Persian and Turkish peoples were the first to grow tulips, with cultivation dating back to 10th-century Persia. They probably reached Anatolia with the advance of the Seljuks, and by the 1400s, tulips were among the most prized flowers, later becoming a symbol of the Ottoman Empire. They were grown in Byzantine Constantinople as early as 1055, but Northern Europeans only learned of them in the 1500s, when diplomats to the Ottoman court observed and reported on them. Tulips quickly spread into Northern Europe and became the focus of a famous investment bubble—the Dutch tulip mania of 1634–1637. They appear frequently in Dutch Golden Age paintings and have remained linked to the Netherlands, which is now the major global producer.

During the 17th-century tulip mania in the Netherlands, a virus called the tulip breaking virus infected bulbs, creating admired variegated patterns in the flowers. While truly broken tulips are no longer cultivated, the closest modern equivalents belong to the Rembrandt group, named after the painter who depicted some of the most admired breaks of his time. Breeding programs have since produced thousands of hybrids and cultivars, in addition to the original species (called botanical tulips in horticulture). Today, tulips are popular worldwide as ornamental garden plants and as cut flowers.

**Description** Tulips are perennial, bulb-forming herbaceous plants that bloom in spring and die back to an underground storage bulb after flowering. Bulbs range from about 1 cm to 5 cm (0.4 to 2 inches) in diameter. Stems bear few leaves; larger species tend to have more, with plants typically carrying two to six leaves, though some species have up to twelve. Leaves are cauline (growing on the stem), strap-shaped, waxy, and arranged alternately, becoming smaller higher up the stem. They are often bluish-green. The bulbs are truncated at the base and elongated toward the tip, covered by a protective tunic that may be smooth or hairy inside. Leaf length varies by species, usually between 10 and 25 cm (4 to 10 inches), but some species exceed 30 cm (12 inches).

**Flowers** Tulip flowers are typically large, radially symmetric (actinomorphic), and hermaphrodite, containing both male and female parts. They are usually erect, rarely pendulous, and most often appear as a single terminal flower. When pluriflor, they produce two to three flowers (e.g., *Tulipa turkestanica*), or up to four, on a single stem (scape) rising from a basal leaf rosette. The flower is generally cup- or star-shaped. Like other members of Liliaceae, the perianth is undifferentiated (perigonium) and arranged in two whorls of three parts (trimerous), forming six free, caducous tepals. The two whorls represent three petals and three sepals, but are called tepals because they look nearly identical. Tepals are usually petal-like and brightly colored, though each whorl may differ or have colored blotches at the base, creating darker patterns on the inner surface. Inner tepals have a small, delicate cleft at the top; outer ones form uninterrupted ovals. The flower has six distinct, basifixed, introrse stamens in two whorls of three, which vary in length and may be smooth or hairy. Filaments are shorter than the tepals and widen toward the base. The style is short or absent, each stigma has three distinct lobes, and the ovary is superior with three chambers.

**Colours** Tulip flowers come in a wide range of colors—reds, yellows, purples, white—but not pure blue (tulips with "blue" in their name usually have a faint violet hue). They lack nectaries. A tulip's color results from two pigments working together: a base color that is always yellow or white, and a second anthocyanin color. The combination of these two determines the visible unitary color. Flower breaking occurs when a virus suppresses anthocyanin production, exposing the base color as a streak. Although tulips can be bred for many colors, black tulips have historically been difficult to achieve. The Queen of the Night tulip comes close to black, though it is not truly black.