Heliotropioideae

Vanilla flower ( Heliotropium arborescens ), inflorescences

The Heliotropioideae are a subfamily within the family Boraginaceae ( Boraginaceae ). For some authors it also has the rank of a family Heliotropiaceae Schrader. This subfamily contains about eight genera with 450 species, and is represented worldwide by the moderate latitudes to the tropics.

Description

There are one to perennial herbaceous plants, subshrubs, shrubs, trees or rarely lianas. The name Boraginaceae indicates the characteristic pubescence of the leaves and stems, which have many of the Central European species. The most change-constant leaves are simple and entire. Stipules are not available.

The flowers are arranged in inflorescences zymösen or stand individually in some Heliotropium species. The hermaphrodite flowers are mostly radial symmetry and usually fünfzählig. Some Heliotropium species are dioecious getrenntgeschlechtig ( dioecious ). The sepals ( sepals ) are at the bottom and the petals ( petals ) are completely fused together and form tube-or plate-shaped stalk flowers. It's just a circle with usually five fertile stamens present ( tetracyclic flower). The stamens are fused with the petals too and are usually at half Kronblattlänge. The usually two carpels form the superior ovaries. In contrast to all other Raublattgewächsen the stylus is here terminally on the ovary and ends in a characteristic, occurring only in this subfamily Griffel-/Narbenkomplex. Here are formed as an exception in the family Boraginaceae with four one-seeded drupes cores, but some taxa have also Klausen as in the whole family common.

Systematics and distribution

They are located worldwide in the tropics to warm temperate latitudes. The subfamily of Heliotropioideae contains four to eight genera with 405-450 species:

• Argusia Böhm: The two or three species are widespread in Central Asia. There are perennial herbaceous plants form the Klausen.
• Ceballosia Kunkel: it contains only one type: Ceballosia fruticosa ( L. f ex G.Kunkel ) G.Kunkel ex Förther: This shrub is common in Macaronesia. It forms Klausen.

• Ixorhea tschudiana Fenzl: This shrub grows only in the Argentine province of Salta ), forming large, winged Klausen.

• Nogalia drepanophylla ( Baker) Verdc. The home is Somalia and southwestern Arabia. It is a succulent plant, forming drupes.

Swell

• Description of the subfamily in the APWesite. ( Section systematics and description)
• Nadja Diane, Harald Förther, Hartmut H. Hilger: A systematic analysis of Heliotropium, Tournefortia, and allied taxa of the Heliotropiaceae ( Boraginales ) based on ITS1 sequences and morphological data. (English )