Draparnaldia
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| Draparnaldia | |
|---|---|
_(19795499774).jpg) | |
| left: Draparnaldia glomerata, right D. fluitans | |
Scientific classification  | |
| Kingdom: | Plantae |
| Division: | Chlorophyta |
| Class: | Chlorophyceae |
| Order: | Chaetophorales |
| Family: | Chaetophoraceae |
| Genus: | Draparnaldia Bory de Saint-Vincent, 1808 |
| Type species | |
| Draparnaldia mutabilis | |
| Species[1] | |
Draparnaldia is a genus of freshwater green algae in the family Chaetophoraceae.[1] It forms branched chains of cells, termed filaments, surrounded by mucilage. It is a cosmopolitan genus with wide distribution and it is usually found in cold aerated waters. They are either attached to sand or grow epiphytically on other aquatic plants. Draparnaldia can be seen growing in clear streams trailing on stones and boulders. Herman S. Forest of The Southern Appalachian Botanical Club has stated that while not common, it is present frequently enough to be recorded in almost all local flora lists of green algae that have been compiled. A multitude of species are present in Lake Baikal, Siberia and have been described by Meyer and Jasnitzky.
Reproduction
Draparnaldia consists of uniseriate filaments (chains of cells arranged in one row), which are attached to a substrate with rhizoids; the plant is surrounded by soft mucilage. The length of the main axis cells are generally equal, with some cells having side branches. Branches are borne in alternating, opposite, or whorls of tufts from the main axis. Tips of branches usually bear long, tapering hairs.[2] Chloroplasts appear as a band within the center of each cell, and may have a smooth or reticulate margin; they have several pyrenoids.[1]
The morphology is highly variable,[2] being dependent upon several environmental conditions.[2][3] The hairs develop through the elongation of the apical cell on the branch tips; as they elongate, the chloroplast is lost. Hair development is affected by the levels of phosphorus, nitrogen, carbon dioxide, and light. Although hair production can be suppressed under lab conditions, they are always present in the field.[3]
Asexual reproduction is by zoospores, or thick-walled aplanospores. Zoospores are produced in the cells of the main axis, and are either all equally sized and biflagellate or dimorphic (two types: smaller and biflagellate or larger and quadriflagellate). Sexual reproduction has also been observed; it is isogamous with biflagellate or quadriflagellate gametes.[1]