Alfaroa
| Alfaroa | ||||||||||||
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Alfaroa mexicana |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Alfaroa | ||||||||||||
| Standl. |
Alfaroa is a genus of evergreen trees from the walnut family(Juglandaceae). It occurs from Mexico to Colombia.
features
The representatives are evergreen trees. The buds are bare. The leaves have no stipules and are opposite or whorled, less often partially alternate. They are pinnate in pairs with 4 to 12 leaflets. The underside of the leaf is dotted with glandular dots, the leaf margin is sawn in young trees, in older trees completely.
The plants are monoecious . The male flowers are in panicles or 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 , as 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 receptaculum and a three-lobed cover leaf, two bracts, one to four sepals and 6 to 10 stamens . The anthers are bare. The pollen grains are around 24 micrometers in diameter and are slightly triangular in polar view. The female flowers are also sessile, have a very small, three-lobed cover leaf that is only fused with the ovary at the base . The cover sheet does not grow into a wing when the fruit is ripe, but remains on the fruit as a small scale. The sepals sit at the top of the ovary. 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 rather large nut fruit with a thin to thick shell. It has no wings and no shell. The nutshell is thin to thick and covered by a thin to thick skin formed by the calyx. It is divided into eight compartments up to the middle. The cotyledons are separate, not entangled, in the fruit.
The germination takes place hypogeous. The first real leaves of the seedling are simple or compound. The knot of the cotyledons has a lacuna and three leaf tracks.
The chromosome number is 2n = 32.
Systematics
Alfaroa is the sister group to Oreomunnea and is part of the walnut family with this and Engelhardia in the subfamily Engelhardioideae.
The genus includes eight species, seven of which Manning mentions in 1978, one ( Alfaroa colombiana ) was first described in 1981:
- Alfaroa colombiana Lozano, Hern. Cam. & S.Espinal-T. : It occurs in Colombia.
- Alfaroa costaricensis Standl. : Mexico to Panama, type species
- Alfaroa guanacastensis D.E. Stone : Costa Rica
- Alfaroa guatemalensis (Standl.) LO Williams & Ant. Molina : Guatemala
- Alfaroa hondurensis L.O. Williams : Honduras
- Alfaroa manningii J. León : Costa Rica
- Alfaroa mexicana D.E. Stone : Eastern Mexico
- Alfaroa williamsii Ant. Molina : Nicaragua and Costa Rica
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
- ^ Alfaroa species list , Tropicos.org, accessed January 8, 2008.
- ↑ Species entry , Tropicos.org, accessed January 8, 2008.