Strasburgeria robusta

Strasburgeria robusta
Systematics
	Rosids
	Eurosiden II
Order :	Crossosomatales
Family :	Strasburgeriaceae
Genre :	Strasburgeria
Type :	Strasburgeria robusta
Scientific name of the genus
	Strasburgeria
	Baill.
Scientific name of the species
	Strasburgeria robusta
	( Vieill. Ex Pancher & Sebert ) Guillaumin

Strasburgeria robusta is an evergreen tree species in New Caledonia from the plant family of strasburgeriaceae in order crossosomatales .

features

Habit and leaves

Strasburgeria robusta is an evergreen tree . The leaves are large, leathery, spiral and have a stalk. The leaf blade is undivided and the leaf margin is slightly serrated. The leaf shape is obovate to spatulate. Stipules are present, the two stipules form a small scale. The leaves have a mucous hypodermis on the upper side. The mesophyll also contains mucous cells.

In the shoot axis (cortex and pulp) there are secretory ducts with mucus. There is no internal phloem in the vascular bundles . Secondary growth takes place over a conventional annular cambium . The xylem has tracheids .

blossoms

The plants are hermaphroditic. The flowers are single. The perianth is arranged acyclically, the calyx spirally. A free hypanthium is absent, a hypogyne extrastaminal disk is present. The perianth is divided into calyx and crown and consists of 13 to 15 leaves. The calyx is spiral and has eight to ten leaves. The leathery sepals stand like roof tiles, become larger and larger inward and also remain on the fruit. The petals stand in a whorl to form five petals like roof tiles. These are fleshy and sedentary.

There are 10 free stamens that are similar and do not grow together. They stand in two circles (diplostemon). All are fertile. The pollen is aperturat with three (to four) apertures, and colportat.

The gynoeceum consists of five intergrown carpels. The ovary is above, five-way and sitting. There is a stylus that is wedge-shaped from the ovary. It remains on the fruit. The only scar is small and heady. The placentation of the ovules is central angular. There are two crassinucellate ovules per compartment, which are pendulous and superposed.

fruit

The fruit is fleshy to not fleshy and round. It is a closing fruit: capsule or berry : berry-like , corky-woody when dry. The diameter is five to six centimeters. The seeds have a fleshy endosperm . They are triangular with a broad, wing-like, opaque hilum . The outer testa ( seed coat ) consists of five to twelve layers of crystal- bearing sclereids . The embryo is well developed with two cotyledons .

Chromosome number

The chromosome number is n = 25.

distribution

The species is endemic to New Caledonia . The tree grows on ultra-basic rock. From the Tertiary fossil pollen is similar to that of Strasburgeria been found in Australia, Tasmania and New Zealand.

Systematics

Within the crossosomatales is Strasburgeria the Schwestertaxon of Ixerba . Both groups have the following features in common: at least in the flowers cells with thickened mucous inner tangential walls; needle-shaped crystals; spiral leaves with a glandular-serrated margin; large flowers with spiral calyx; flat filaments; Anthers over three millimeters long; Carpel sessile, epitropic with a long hollow stylus that is retained on the fruit; Base chromosome number of 25.

The species was initially described as a species of the genus Montrouzieria (family Clusiaceae ) and in 1876 was placed in its own genus as Strasburgeria calliantha by the French botanist Henri Ernest Baillon . (Adansonia, xi. P. 372). He named the genus in honor of the German botanist Eduard Strasburger . The species name was corrected by Guillaumin in 1942 in Strasburgeria robusta .

supporting documents

Kenneth M. Cameron: On the phylogenetic position of the New Caledonian endemic families Paracryphiaceae, Oncothecaceae, and Strasburgeriaceae: a comparison of molecules and morphology. In: The Botanical Review. Vol. 68, No. 4, 2002, ISSN 0006-8101 , pp. 428-443, doi : 10.1663 / 0006-8101 (2002) 068 [0428: OTPPOT] 2.0.CO; 2 .
Watson, L., and Dallwitz, MJ 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 1st June 2007
Strasburgeriaceae on the AP website

Individual evidence

↑ K. Oginuma, J. Munzinger, H. Tobe: Exceedingly high chromosome number in Strasburgeriaceae, a monotypic family endemic to New Caledonia. In: Plant Systematics and Evolution. Vol. 262, No. 1/2, 2006, ISSN 0378-2697 , pp. 97-101, doi : 10.1007 / s00606-006-0451-8 .