Holmbergia tweedii
| Holmbergia tweedii | ||||||||||||
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| Holmbergia | ||||||||||||
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| Holmbergia tweedii | ||||||||||||
| ( Moq. ) Speg. |
Holmbergia tweedii is the only species of the monotypic plant genus Holmbergia from the subfamily Chenopodioideae in the foxtail family(Amaranthaceae). The climbing plant with fleshy fruits is found in South America .
description
Appearance and leaf
Holmbergia tweedii is a climbing shrub or shrub with a height of up to 3 meters. The protruding, back and forth curved shoot axes are soft-haired when young, later balding and striped at the base.
The alternate, sometimes almost opposite, leaves have a 2 to 10 millimeter long petiole. The fleshy, green leaf blades are 10 to 35 millimeters long and 10 to 22 millimeters wide, glabrous, with a distinct midrib. Their shape is usually ovate, obovate, lanceolate or elliptical (sometimes almost spear-shaped or rhombic). The leaf margin is entire. The leaf anatomy corresponds to the "normal" (non-wreath) type of the C3 plants .
Inflorescence and flower
Holmbergia tweedii is monoecious ( monoecious ) separate sexes. The inflorescences consist of clusters of male flowers in interrupted, terminal false spikes and female flowers in the leaf axils. The male flowers (without bracts) have an inflorescence consisting of five tepals 1.5 millimeters long with a hood-like tip connected to one another in the lower half . In front of the tepals there are five stamens that arise from a discus. The anthers protrude from the flower. The female flowers each have a cover sheet (bracteole). They consist of a delicate-skinned flower cover of five tepals, which are connected to the middle and slightly hairy at the tip, 0.5 to 1 millimeter long with a green central nerve, and an ovary with two subtle, protruding stigmas.
Holmbergia tweedii flowers in their natural range from March to June.
Fruit and seeds
At the time of fruiting, the unchanged bloom cladding leaves are still present at the base of the much larger fruit. The fruit, which does not fall off when the fruit is ripe, increases in size to 3 to 5 × 3 to 4 millimeters, becomes purple-red or blood-red and spongy berry-like, it is almost spherical or ellipsoidal, compressed laterally. Their fleshy, bloated pericarp does not adhere to the seed. The vertically standing seed, 3 millimeters in diameter, has a black, smooth and shiny, hard seed coat . The ring-shaped embryo surrounds the abundant floury endosperm .
Occurrence
Holmbergia tweedii is common in South America ( Argentina , Bolivia , Paraguay and Uruguay ). It grows on salty soils , for example in salt marshes , together with other halophytes .
Systematics
Holmbergia tweedii belongs to the tribe Atripliceae (Syn .: Chenopodieae) of the subfamily Chenopodioideae in the family Amaranthaceae .
It was first described in 1849 under the name ( Basionym ) Chenopodium tweedii by Alfred Moquin-Tandon . The genus Holmbergia was established in 1909 by Cristóbal Mariá Hicken (In: Apuntes de Historia Natural 1, p. 65). The type species is Holmbergia exocarpa (Griseb.) Hicken , which is now considered a synonym. In 1916 Carlo Luigi Spegazzini grouped Chenopodium tweedii in the genus Holmbergia .
Synonyms of Holmbergia tweedii (Moq.) Speg. are Chenopodium exocarpum Griseb. , Chenopodium tweedii Moq. and Holmbergia exocarpa (Griseb.) Hicken .
swell
- Elizabeth H. Zacharias, Bruce G. Baldwin: A Molecular Phylogeny of North American Atripliceae (Chenopodiaceae), with Implications for Floral and Photosynthetic Pathway Evolution. In: Systematic Botany , Volume 35, Issue 4, 2010, pp. 839-857. doi : 10.1600 / 036364410X539907 (sections description, occurrence and systematics)
Individual evidence
- ^ Alfred Moquin-Tandon in AP de Candolle & ALPP de Candolle: Prodromus systematis naturalis regni vegetabilis , 13 (2), 1849, p. 63. (first description)
- ↑ Holmbergia tweedii at Tropicos.org. Missouri Botanical Garden, St. Louis