Klebsormidium

Klebsormidium is a genus of filamentous charophyte green algae comprising 20 species.^[1] The name was proposed in 1972 to resolve confusion in application and status of Hormidium^{[Note 1]} and was given for the German botanist Georg Albrecht Klebs.^{[Note 2]}

Klebsormidium
Scientific classification
Kingdom:	Plantae
Class:	Klebsormidiophyceae
Order:	Klebsormidiales
Family:	Klebsormidiaceae
Genus:	Klebsormidium P.C.Silva, Mattox & W.H.Blackwell[1][2]
Type species
Klebsormidium flaccidum P.C.Silva, Mattox & W.H.Blackwell[1]
Species
See species list.

Klebsormidium bilatum

The algae occurs mostly in soil and on moist substrates, nevertheless, aquatic and one marine species are also known. Many Klebsormidium-species are able to synthesize substances for UV protection, the so-called mycosporine-like amino acids. The draft genome sequence of Klebsormidium nitens NIES-2285 (called K. flaccidum at the time of publication) was published in 2014.^[3]

Description

Klebsormidium forms uniseriate (one cell thick), unbranched filaments. Cells are cylindrical or barrel-shaped. The cell wall may be thin or thickened, and is sometimes made of H-shaped pieces. Each cell contains a single parietal chloroplast which encircles around 40 to 70% of the cell wall, usually with a single pyrenoid.^[4]

Klebsormidium reproduces asexually but not sexually. It produces zoospores with two flagella, which are released from cells through a pore. It can also produce aplanospores and akinetes.^[4]

The genus can be difficult to distinguish from Ulothrix, but Ulothrix tends to have chloroplasts that are wider and encircling nearly all of the cell.^[4]

Species

The valid species currently considered to belong to this genus are:

• Klebsormidium acidophilum
• Klebsormidium bilatum
• Klebsormidium crenulatum
• Klebsormidium dissectum
• Klebsormidium drouetii
• Klebsormidium elegans
• Klebsormidium flaccidum
• Klebsormidium fluitans
• Klebsormidium fragile
• Klebsormidium klebsii
• Klebsormidium lamellosum
• Klebsormidium montanum
• Klebsormidium mucosum
• Klebsormidium nitens
• Klebsormidium pseudostichococcus
• Klebsormidium scopulinum
• Klebsormidium sterile
• Klebsormidium subtile
• Klebsormidium subtilissimum
• Klebsormidium tribonematoideum

The species of Klebsormidium are in critical need of a taxonomic revision. Traditional morphological characteristics used to delimit the taxa, such as the width of filaments or shape of cells, are unreliable and do not map well to phylogenetic groups.^[5]

Notes

1. Hormidium nitens G.A.Klebs 1896
2. Georg Albrecht Klebs (1857-1918) Dinophyceae, Chrysophyceae and Xanthophyceae specialist