Oreomunnea
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Oreomunnea is a genus of evergreen trees from the walnut family(Juglandaceae). It occurs in Mexico and Central America.
features
The representatives are evergreen trees. The buds are bare. The leaves have no stipules and are opposite. They are pinnate in pairs with 4 to 12 leaflets. The underside of the leaf is dotted with glands, the leaf margin is sawn in young trees or completely, in older trees completely.
The plants are monoecious . The male flowers are in paniculate catkins individually or together with a central female spike . The inflorescences are terminal or laterally on branches. The kittens are all multi-flowered and pendulous. The flowers have a broad bract , which is three-lobed in both sexes. Both sexes also have two bracts and four sepals . The sepals are often reduced in male flowers. The male flowers are sessile, have a round or elongated receptacle and a three-lobed cover leaf, two bracts, one to four sepals and 8 to 23 stamens . The anthers are bare. The pollen grains have a diameter of around 21 micrometers (19 to 23) and are slightly triangular in polar view. The female flowers have a short stalk. Vorblatt Brakteolen and are connected to the lower half of the ovary grow together, the sepals of the upper half. The carpels are median. The scar surfaces are short, almost spherical to horseshoe-shaped and are at the tip of elongated stylus branches .
The fruit is a short-stemmed, medium-sized nut fruit . It has a large, front three-lobed wing, which emerges from the cover sheet, and a rear, two-lobed wing, which emerges from the bracteoles. The pericarp is rather thin and covered by a thin skin that emerges from the sepals. The interior of the fruit is subdivided by thin septa, in the middle into eight compartments, partly further subdivided by additional protrusions of the pericarp. The cotyledons are separate, not entangled, in the fruit. The fruit and wings are larger than those of the Asian genus Engelhardia .
The germination takes place hypogeous. The first real leaves of the seedling are simple. The knot of the cotyledons has a lacuna and three leaf tracks.
The number of chromosomes as with all representatives of the subfamily Engelhardioideae 2n = 32nd
Systematics
Oreomunnea is part of the walnut family with Alfaroa and Engelhardia in the subfamily Engelhardioideae.
The genus includes two types:
- Oreomunnea pterocarpa Oerst. , in Costa Rica, the type species
- Oreomunnea mexicana (Standl.) J.-F.Leroy , in Mexico and Central America.
However, the two species do not form a common family group, the genus is paraphyletic with respect to the genus Alfaroa :
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supporting documents
- Wayne E. Manning: The Classification within the Juglandaceae . Annals of the Missouri Botanical Garden, Vol. 65, 1978, pp. 1058-1087.
- Paul S. Manos, Donald E. Stone: Evolution, Phylogeny, and Systematics of the Juglandaceae. Annals of the Missouri Botanical Garden, Volume 88, 2001, pp. 231-269.
Individual evidence
- ↑ Paul S. Manos, Pamela S. Soltis, Douglas E. Soltis, Steven R. Manchester, Sang-Hun Oh, Charles D. Bell, David L. Dilcher, Donald E. Stone: Phylogeny of Extant and Fossil Juglandaceae Inferred from the Integration of Molecular and Morphological Data Sets . Systematic Biology, Volume 56, 2007, pp. 412-430, doi : 10.1080 / 10635150701408523