Linaceae

Linaceae is a cosmopolitan family of Magnoliopsid or dicotyledonous plants of about 250 species worldwide that cover much of the planet. The family includes herbaceous or rarely woody plants, and large trees in the tropics. Belonging to the order Malpighiales.

General information

A cosmopolitan family consisting of about 250 species. It is made up of trees, shrubs, annual and perennial herbs. It occupies desert, Mediterranean regions, jungles, steppes and the humid and dry Puna. In general they are herbs or small bushes, annual, biennial or perennial. There are 14 genera, classified into two subfamilies: Linoideae and Hugonioideae often recognized as a distinct family, the Hugoniaceae.

The family is of ancient origin and is closely related to the family Erythroxylaceae, with which some ancient taxonomists linked it. The leaves of the Linaceae are always simple.

In the Linoideae, the largest genus is Linum , with 180 to 200 species, including the cultivated flax Linum usitatissimum. Members of the Linoideae include mostly annual and perennial herbaceous plants, as well as woody subshrubs, shrubs, and small trees (Tirpitzia) that inhabit temperate and tropical latitudes in Eurasia, Africa, Australia, and the Americas.

Hugonioideae are vines, shrubs, and trees and are almost entirely tropical in distribution. The largest genus of the Hugonioideae is Hugonia, with approximately 40 species. In addition to their growth habits and geographic distribution, the genera Linoideae and Hugonioideae can be differentiated by the number of fertile stamens (5 in Linoideae, 10 in Hugonioideae) and the type of fruit: capsules in Linoideae and fleshy drupe in the shape of a fruit, in the Hugonioideae which produces many different types of fruit, eaten by birds, which disperse the seeds.

Description

They have entire simple leaves, almost always alternate, the leaves are opposite or alternate, seated, without stipules, although sometimes they are stipulated. Cymose inflorescences. Hermaphroditic, actinomorphic, pentameric or very rarely tetrameric flowers, these are much more frequent in the tropics, showy petals, quickly drooping, light in color, with a narrow nail. Calyx with free sepals. Corolla with free or slightly welded petals at the base. Androecium with 4 or 5 stamens alternating with the petals welded together at the base, sometimes alternating with 1 whorl of staminodes. Ovary superior, with 4-5 carpels, 4-5 cavities and 4-5 styles. Linear or capitate stigmas. Diplostemonas with stamens welded to the disc; ovary superior, pentacarpellate, without carpicus, with free or slightly welded styles; two ovules per carpel, with a false internal septum with 10 cavities. Fruit without a beak, in a loculicidal capsule or rarely in a drupe. Fruit in a loculicidal capsule, with 8-10 valves. Two seeds per cavity, separated by a pseudoseptum.

Uses

A species of agricultural relevance is flax, Linum usitatissimum, cultivated to obtain textile fibers and oils.

Synonymy

• Hugoniaceae Arn. Ctenolophaceae (H. Winkl.) Exell & Mendonca.

Genres

Genus in the subfamily Linoideae

• Anisadenia
• Cliococca
• Hesperolinon
• Linum
• Radiola
• Reinwardtia
• Sclerolinon
• Tirpitzia

Genus in the subfamily Hugonioideae

• Durandea
• Hebepetalum
• Hugonia
• Indorouchera
• Philbornea
• Roucheria