[3] The base of the plant can form a clumpy trunk-like structure, measuring up to 1 meter in height and 50 cm in diameter.
[3] The utricle (a sac that surrounds the fruit) is 2-5mm,[8] dark brown with minor winged margins,[7] and contains two stigmas.
[9] Carex secta plants thrive in open water environments, which can include swamps, rivers, lakes, ponds, and streams.
[12] Due to the ability of Carex secta to flourish with saturated roots, they are frequently found in riparian planting margins across the country.
[9] At the head of the Gorge River in South Westland, which is about 700 metres above sea level, Carex secta is found above its typical altitude range.
[9] In the Copland Valley, also in South Westland, Carex secta can be found growing at 450 meters above sea level in swamps where geothermal activity occurs nearby.
[9] Carex secta flowers from late September to early December;[7] this can slightly vary depending on environmental conditions.
[17] Because of this, when vegetation is cleared in wetlands, allowing light to reach ground level, the seeds will germinate in mass.
[19] These species include Diplopseustis perieresalis, Orocrambus angustipennis, Tmetolophota sulcana, Sagephora exsanguis, Megacraspedus sp..[19] The Hemiptera species that feed on the leaves and seeds of the Carex secta include Rhopalimorpha obscura and Rhopalimorpha lineolaris.
[20] Where soil and environmental conditions allow, wilding pines (e.g., Pinus radiata), Scotch broom (Cytisus scoparius), Willow species (Salix spp.)
and blackberry (Rubus fruticosus) species frequently outcompete native plants, such as Carex secta.
[6] The spread of invasive willows, with their large canopies, prevents light from reaching the ground level which limits the opportunities for the growth of Carex secta in what would otherwise be their ideal habitat.
[25] The Carex virgata inflorescences are clearly branched and never droop, as the panicle remains rigid and with the basal branchlets often further apart.
[27] The proverb referred to Carex secta as a trustworthy and reliable place where you could stop to rest during your journey across the swampy lands.
[28] Another benefit stemming from the presence of Carex secta in waterways is the enhancement of water quality due to the reduction in sediment runoff from agriculture practices.
[17] The drooping form of the leaves of Carex secta provides an additional benefit of shading over the water, helping to reduce eutrophication (which can be a major issue in some waterways).
The tussock form of Carex secta, raised above the water, provides excellent shelter and nesting sites for ground birds.