''Nitellopsis obtusa'' is a large freshwater

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

. It is also known by the common name starry stonewort.Minchin, D., Boelens, R. and Roden, C. 2017. The first record of ''Nitellopsis obtusa'' (N.A.Desvaux) J.Groves (Charophycese, Characeae) in Ireland (H9, H10) ''Irish Naturalists' Journal'' 35:(2):105 - 109 This alga grows to a length of over , is bright translucent green and has branches growing in whorls from the main axis the plants easily break up. It is easily distinguished from other charophytes by star-shaped bulbils which permit vegetative reproduction.

Description

''Nitellopsis obtusa'' has long, fairly straight branches arranged in whorls, attached at nodes to the stem at an acute angle. Both stem and branches are about in diameter, and the internodal lengths of stem consist of a single cell which may be several centimetres long. Stems may be up to or even longer and form dense masses. When in active growth, the colour is light green. At the base of the main stems, there may be creamy-white bulbils. The rhizoids are star-shaped. Plants are either male or female. The

oogonia An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in larg ...

(female reproductive structures) form at the base of upper branchlets and orange to red

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...

s can occur, which help distinguish this alga from the rather similar musk-grass and brittlewort.

Habitat

This alga grows in freshwater to a depth of over , on soft substrates such as silt, sand and accumulations of

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

. It tends to grow in deep, slow moving water where other plants are scarce, typically near docks and marinas.

Distribution

''Nitellopsis obtusa'' is widely dispersed in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. It is known from only a few sites in the British Isles, and these include Cosmeston Lake in the

Vale of Glamorgan The Vale of Glamorgan ( cy, Bro Morgannwg ), often referred to as The Vale, is a county borough in the south-east of Wales. It borders Bridgend County Borough to the west, Cardiff to the east, Rhondda Cynon Taf to the north, and the Bristol C ...

. It has

invaded An invasion is a military offensive in which large numbers of combatants of one geopolitical entity aggressively enter territory owned by another such entity, generally with the objective of either: conquering; liberating or re-establishing con ...

the Laurentian Great Lakes in North America.

References

{{Taxonbar, from=Q2345622 Charophyta