''Lagerheimia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

in the family

Oocystaceae Oocystaceae is a family (biology), family of green algae, in the class Trebouxiophyceae. Molecular phylogenetic studies mostly (but not always) place the family in the order Chlorellales, as sister to Chlorellaceae. The Type (biology), type genus ...

. It is commonly found in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

habitats all over the world, although some species are rare and have only been recorded from Europe or the United States. The genus name of ''Lagerheimia'' is in honour of

Nils Gustaf Lagerheim Nils Gustaf Lagerheim (1860–1926) was a Swedish botanist, mycologist, phycologist, and pteridologist. Today, he is best remembered as one of the chief architects of pollen analysis as a tool in botany, alongside his student Ernst Post. Car ...

(1860–1926), who was a Swedish botanist, mycologist, phycologist, and

pteridologist #REDIRECTFern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having spec ...

. The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

Giovanni Battista De Toni Giovanni Battista de Toni (2 January 1864, Venice – 31 July 1924, Modena) was an Italian botanist, mycologist and phycologist. In 1885 he graduated from the University of Padua, where he studied natural sciences and chemistry with Pier An ...

and

Robert Hippolyte Chodat Robert Hippolyte Chodat (4 June 1865, Moutier – 28 April 1934) was a Swiss botanist and phycologist who was a professor and director of the botanical institute at the University of Geneva. He studied medicine and botany at Geneva, where he was ...

in Nuova Notarisia vol.6 on page 86-90 in 1895.

Description

''Lagerheimia'' consists of solitary cells. Cells are spherical, ellipsoidal, ovoid, polyhedral, or citriform (lemon-shaped), with one to several spines at the poles; some species also have spines at the equators. A layer of

mucilage Mucilage is a thick gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion, with the direction of their movement always opposite to that of the secretion of ...

around the cell may be present. Cells contain a parietal

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

with one

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

. Species identification is based on the shape of the cells, placement and length of the spines, and presence or absence of tubercles at the base of the spines. Species with tubercles at the base of their spines have been classified in a separate genus, called ''Chodatella''; however, modern authors do not recognize this split. The genus is similar to '' Franceia'', which has spines distributed all over the cell surface. It may also be confused with single-celled forms of ''

Desmodesmus ''Desmodesmus'' is a genus of green algae in the family Scenedesmaceae. It is the only chlorophyll-containing organism known to have caused human infections in immunocompetent individuals. All known cases involved open injuries occurring in fre ...

'', a genus that usually has coenobia of four or eight cells.

Reproduction

''Lagerheimia'' reproduces asexually by

zoospore A zoospore is a motile asexual spore that uses a flagellum for locomotion in aqueous or moist environments. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Certain zoospores are ...

s or

autospore Autospores are a type of spores that are produced by algae to enable asexual reproduction and spread. They are non-motile and non-Flagellated cell, flagellated Aplanospore, aplanospores that are generated within a parent cell and have the same sha ...

s. Zoospores have two

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

. When reproducing with autospores, 2, 4, or 8 are formed within the mother cell and are released when the mother cell wall ruptures. Reports of

sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...

have not been confirmed.

Taxonomy

''Lagerheimia'' is placed in the family ''

''. The cell wall

ultrastructure Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a c ...

of '' Lagerheimia subsalsa'' is similar to that of some species of ''

Oocystis ''Oocystis'' is a planktonic genus of mostly freshwater green algae of the Family (biology), family Oocystaceae. It is the type genus of its family. ''Oocystis'' is mostly found in freshwater habitats and has a cosmopolitan distribution. A few sp ...

'', and consists of several layers of

microfibril A microfibril is a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose. It is usually, but not always, used as a general term in describing the structure of protein fiber, e.g. hair and sperm tail. Its most frequently o ...

s. Microfibrils are perpendicular from one layer to the next. Because ''Lagerheimia'' appears similar to one-celled forms of ''Desmodesmus'', some authors have doubted the validity of this genus. However, ''Lagerheimia'' strains are phylogenetically placed within the class

Trebouxiophyceae The Trebouxiophyceae, also known as trebouxiophytes, are a class of green algae, in the division Chlorophyta. Members of this class are single-celled, colonial, or multicellular and are found in freshwater, terrestrial or marine habitats worldwid ...

. In its current

circumscription Circumscription may refer to: * Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthr ...

, ''Lagerheimia'' is

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

: some species are more closely related to '' Franceia'' than to other ''Lagerheimia'' species.

References

{{Taxonbar, from=Q6472018 Trebouxiophyceae genera Oocystaceae Freshwater algae