- Dahlgrenodendron
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Dahlgrenodendron Scientific classification Kingdom: Plantae (unranked): Angiosperms (unranked): Magnoliids Order: Laurales Family: Lauraceae Genus: Dahlgrenodendron Dahlgrenodendron is an endangered genus of plant in family Lauraceae. They are evergreen "lauroide" trees belonging to the tropical or templated Laurel forest habitat, a type of Cloud forest in Africa and South Africa.
Contents
Overview
The genus name, is dedicated to Rolf Dahlgren. professor at the University of Copenhagen, that found the first species of genus in Larel forest habitat in Eastern Cape Province, KwaZulu-Natal, South Africa. The genus is characterized by an extremely rare combination of characters that have occured in the species in its own distinct genus. There is little information regarding the species due to its scarcity, 200 individuals. The species Dahlgrenodendron natalense is endangered and is known from a scarce number of localities; it has not been found again at Ngoye forest, despite several searches and it is probably extinct at this locality; there are at least two plants in the Nqutu area; a single large tree, which is dying of old age, is in Umdoni Park; the largest number of trees are found in the remnant forest patches between the Msikaba and Umtamvuna Rivers.[1]
laurel forest evergreen hermaphodyte tall trees with leaves opposite, penninerved, net-veining conspicuous on both surfaces. Inflorescences 3-flowered cymules, arranged on young growth or on short-shoots, with small, caducous bracts. The flowers are bisexual, 3-merous, greenish white. Perianth: tube deeply urceolate. Tepals subequal. Male flowers with 9 fertile stamens, the third whorl with glands; filaments much shorter than anthers; anthers 2-thecous, the first and second whorl introrse, the third whorl extrorse; pollen with a well developed, striate exine, apparently unique for the family Lauraceae; staminodes of whorl four conspicuous, ovate-triangular. Ovary sessile, more or less immersed in a receptacle, narrowed into slender style and small stigma. the fruit completely enclosed in accrescent perianth tube; tepals persistent. The fruit, a berry, is dispersed by birds. Seed with a delicate testa.[2]
Ecology
The South African monotypic Dahlgrenodendron plant genus come from a relict species living in the Tertiary in a more warmer and humid climate conditions in the continent, in the Cape province area of laurel forest, and therefore, more distributed in the Tertiary. It is a palaeo endemic botanical genus, usually found on forest margins, both next to and away from stream banks. A few individuals have been recorded from within climax forest, but these were invariably very old and senescent.[3]
The ecological requirements of the genus are those of the laurel forest and like most of their counterparts laurifolia in the world, it is vigorous species with a great ability to populate the habitat that is conducive. The natural habitat is rainforest which is cloud-covered for much of the year. The species is found in forests that face threats of destruction by human deforestation.
Because of the special lack of worldwide knowledge about the family lauraceae in general, very little is known about their diversity. Recent monographs of the small and medium genera of lauraceae with up to 100 species per genus have produced a high increase in the number of known species. This high increase is expected for other genera as well, particularly for those with more than 150 species recorded, bringing an expected considerable increase in the total number of species of the family.
A related vegetal community evolved millions of years ago on the supercontinent of Gondwana, and species of this community are now found on several separate areas of the Southern Hemisphere, including South America, Africa, New Zealand, Australia and New Caledonia.
Species
It contains the following species (but this list may be incomplete):
- Dahlgrenodendron natalense, W. Burger
References
Categories:- Dahlgrenodendron
- Laurales genera
- Laurales stubs
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