Mangrove Ferns
| Mangrove Ferns | ||||||||||||
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Mangrove fern ( Acrostichum aureum ) |
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| Scientific name | ||||||||||||
| Acrostichum | ||||||||||||
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Mangrove ferns ( Acrostichum ) are a genus of plants within the tree fern family (Pteridaceae). The only three species thrive pantropically in marshland, especially in freshwater-influenced marginal areas of mangroves .
description
Acrostichum species are robust, perennial, herbaceous plants with upright or ascending rhizomes and fleshy roots with ventilation tissue (= aerenchyma). The fronds are simply pinnate and up to 4.5 meters long; the petiole and the lower part of the rachis have brownish scales. The feathers are short stalked or sessile and are up to 40 centimeters long. The fronds are somewhat dimorphic; H. the fertile short-lived fronds have up to a third longer petioles and narrower leaf pinna than the sterile long-lived fronds. The sporangia are arranged acrostichoid, i. H. they are distributed over the entire underside of the leaflets and are not piled up in discrete sori . When the spores ripen, the color of this sporangia layer changes from white to green (= immature) and black (= ripe) to brown (after the spores have been released).
Systematics
The genus Acrostichum was established by Carl von Linné . The type species of the genus is Acrostichum aureum
There are only three species within the genus Acrostichum :
- Acrostichum aureum L .: Pantropical species
- Acrostichum danaeifolium Langsd. & Fish. : Neotropic
- Acrostichum speciosum Willd. : Tropical Asia
ecology
Acrostichum danaeifolium is the largest species with fronds up to 4.5 meters in length. It grows in freshwater and brackish estuaries near the coast and is the least salt-tolerant. Acrostichum aureum is somewhat smaller with fronds of up to 3.5 meters, grows in brackish water and mangroves and is more salt-tolerant. Acrostichum speciosum is the smallest and most salt-tolerant species, which sometimes penetrates into the sea-near mangroves with strong tidal influence. Although mangrove ferns grow in constantly moist or flooded habitats, the formation of their fertile fronds is seasonally limited to a few summer months. The spores can float on the water surface for a while before sinking. They therefore germinate on the bank edges at the height of the water's highest level, where the gametophytes develop.
literature
- PB Tomlinson: The Botany of Mangroves. Cambridge University Press, Cambridge, 1986. 419 pp. ISBN 0-521-46675-X
Web links
Individual evidence
- ↑ a b Klaus Mehltreter, Mónica Palacios Ríos: Phenological studies on Acrostichum danaeifolium (Pteridaceae, Pteridophyta) at a mangrove site on the Gulf of Mexico . In: Journal of Tropical Ecology . tape 19 , no. 2 , 2003, p. 155-162 , doi : 10.1017 / S0266467403003171 .