Supported by detailed phenetic macro- and micromorphological characters, ecology, chorological studies, numerical and phylogenetic analysis, and all known data about Eurasian species of Carex muricata group (sect. Phaestoglochin), together with their biogeography, we have
redefined this group and its subordinate aggregates. Four new taxa are described, illustrated and compared with putative related species: Carex spicata subsp. andresii, endemic to the inner part of the Iberian Peninsula, has the perigynum beak smooth and slightly corky
at the base. Carex omeyica, from the southern mountains of Spain and North Africa, has erect-spreading oval perigynia and oval brown glumes without scarious margins. Two new subspecies of C. muricata are described: C. muricata subsp. cesanensis, from
European mountains, has a big trullate perigynium 4.5–5.25 mm long with a short beak, and C. muricata subsp. ashokae, from the Eastern European Mountains to the Himalaya, has an oval perigynium 5–6 mm long with a longer beak. On the other hand, C. pairae
is not a taxon subordinate to C. muricata. A key to the new and related taxa belonging to the aggregate is included.