Flax is a genus of herbaceous plants in the Linaceae family. It counts about 200 species. Flax is a valuable spinning and oil-bearing crop.
A perennial, less often a perennial or annual herb or semi-shrub. Leaves are sessile, alternate, less often opposite or lower whorled; linear, lanceolate, linear-lanceolate, obovate, oblong, narrow-elliptic or spatulate, smooth-edged or finely serrate, naked or pubescent, with 1 or 3-5 parallel veins varyingly expressed; sometimes with 2 brownish stipular glands at leaf base.
Flowers 5-membered, oviparous, actinomorphic, heterostyled and entomophilous, or homologous and self-pollinated; aggregated in cymose inflorescences. Sepals are loose, entire, tortuate, with petiolate glandules along the edges, ciliate or white-perepinnate, without glandules or cilia. Petals are loose, with a marigold (sometimes united in a short tube), longer than tepals, of various colors (blue, blue, yellow, less frequently pink, purple, red or white). Stamens 5, alternating with petals; stamen threads at base deltoid-extended, usually free or fused at the base itself, rarely stamen threads fused along the full length, embrace boll and rise above it in the form of a tube; sometimes acicular staminodes are present. Pollen is usually ellipsoidal, less often spheroidal, rather large, 45-90 µm. The exine is reticulate. Most heterostylous species are characterized by dimorphism of pollen grains. The surface pattern of the exine of short-stalked forms and some homologous species is formed by even rows of outgrowths, identical in shape and size. In long-stalked forms and in some other homogeneous species, these outgrowths differ in shape and size. The gynoecium is composed of 5 fruiting sepals. The ovary is upper, 5-nucleated. Stylodia are 5, free. Stigmas are linear, oblong or cephalic.
Fruit is a septate boll (1.8) 2-7 (8) mm long, (1.8) 2-7 (8) mm wide, globular, flattened-spherical, globular-ovoid or ovoid, opening with 10 one-seeded segments, rarely or almost not opening. Bolls rounded, less frequently 10-sided or 5-sided on cross-section; they are divided by septa into 5 sockets, each containing 2 seeds, which are in turn separated from one another by false septa. Seeds (1.1-1.4) 2-5 mm long, (0.7) 1-3 mm wide, obovate or ellipsoidal, elliptic in cross-section in most species, rarely rounded or triangular. Seeds are predominantly dark brown, sometimes light brown (in the cultivated species Linum usitatissimum the seeds may also be yellow, olive, green, with a reddish or blackish tint).Distribution and ecology
Species of the genus grow in temperate and subtropical regions of both hemispheres. They occur in different ecological conditions, but more often on dry stony, clay, limestone and grassy slopes, in plains and mountain steppes, in subalpine and alpine meadows, sometimes in salt marshes.
Flax has been cultivated since time immemorial, but it is difficult to decide unequivocally where its original homeland is. Regarding annual flax, it is most likely that it comes from the Eastern Mediterranean (Transcaucasia, Anatolia, Western Persia). It easily goes wild, becomes difficult to cultivate and is shown by authors in many countries as a wild or feral plant, sometimes even as a weed. There is a lot of feral flax in southern Russia.
The genus Flax includes more than a hundred species, of which the most important is Common Flax, or spinning flax (Linum usitatissimum L. ) - an annual naked or nearly naked (without hairs) herb; stem height from 30 to 60 cm, but in warm countries, such as India, even higher; branching only in the upper part, in inflorescence; leaves lobed, narrow-lanceolate; flowers gathered upward in the form of a false umbrella; sepals pointed, finely ciliated; petals blue with a grayish tint, sometimes white, broadly oblong; anthers blue; seedpod (linseed head in common parlance) almost spherical; seeds glossy.