HallströmHallstrom

Nomastrum hallströmii, commonly referred to as HallströmHallstrom in informal contexts, is a species of freshwater green algae belonging to the genus Nomastrum. This microscopic organism is notable for its distinctive, star-shaped colonial structure, which consists of numerous cells arranged in a radial pattern. The species was first described by Swedish botanist and algologist Carl Linnaeus the Younger in the 18th century, though it was later reclassified and studied extensively by Swedish researcher Carl Hallström, after whom it is named.

Nomastrum hallströmii is typically found in freshwater environments such as ponds, lakes, and slow-moving streams, often attached to submerged vegetation or detritus. The colonies are usually spherical or slightly flattened, with cells radiating outward from a central point. Each cell is surrounded by a gelatinous sheath, contributing to the colony’s cohesive structure. Under a microscope, the species exhibits a characteristic appearance with 8–16 radiating arms, though variations in cell number can occur.

This alga plays a role in aquatic ecosystems, contributing to primary production and serving as a food source for small invertebrates. Its presence is sometimes monitored in ecological studies to assess water quality, as certain conditions—such as nutrient levels or pollution—can influence its distribution and abundance. Nomastrum hallströmii is not considered harmful to humans or aquatic life but is primarily of interest to researchers studying algal taxonomy and aquatic microbiology.

Due to its small size and relatively simple structure, Nomastrum hallströmii is often used as a model organism in laboratory settings for studying cell division, colony formation, and environmental adaptations in algae. Its classification within the Nomastrum genus is part of broader phylogenetic research into green algae, particularly those belonging to the order Chlorococcales.