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Introduction
Large-headed sedge is a distinctive coastal species of perennial, rhizomatous sedge that is found in North America and Asia in coastal dunes and beaches. In North America, it is restricted to the Pacific Coast, where it is reported from Alaska, British Columbia, Washington and Oregon (USDA 2011). It has also been reported from New Jersey (Wooton 2007) where it is potentially invasive. In British Columbia, this species has been reported along the coast from the US border north to Haida Gwaii.
This is an easily recognized, low-growing (10-30 cm tall) species of Carex that stands out in beach/dune habitats and is usually dominant. It may be found with other beach/dune specialists such as beach pea (Lathyrus japonicus var. maritimus). The large brown seed heads and sharply angled stems are distinctive.
Populations of this species may be viewed in the Vancouver area at Iona Beach Regional Park (Richmond) and Boundary Park Regional Park (Delta).
Species Information
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expanded illustration for this species.
General: Perennial herb from long, spreading rhizomes; stems 10-30 cm tall, arising singly or a few together, usually shorter than the leaves.
Leaves: Sheaths brownish or blackish, breaking into threads at the bases, persistent; blades 2 to 5 per stem, channeled, gradually tapering to the tips, 4-8 mm wide.
Flowers: Spikes either male or female, unstalked, the male inflorescence with many aggregated spikes in a cylindrical, 3.5- to 5-cm long by 1- to 1.5-cm wide head, the female inflorescence with many aggregated spikes in a cylindrical to egg-shaped, 3.5-8 cm long by 2.5-5 cm wide head; bracts lacking in the male inflorescence, the female inflorescence with several to numerous bracts enlarged at the bases, with small-bristled teeth, up to 6 cm long.
Fruits: Perigynia lanceolate to egg-shaped, 1-1.5 cm long, 4-6 mm wide, brownish to brownish-yellow, plano-convex, with small-bristled teeth above, shiny, strongly nerved on both faces, crowded, ascending to spreading, short-stalked, the beaks 5-7 mm long, as long as the bodies of the perigynia, bidentate; female scales egg-shaped, dark to light brown, with translucent margins, usually shorter and narrower than the perigynia; stigmas 3; achenes lens-shaped, 3.5-4 mm long.
The table below shows the species-specific information calculated from original data (BEC database) provided by the BC Ministry of Forests and Range. (Updated August, 2013)
Wooton, Louise. 2007. First Report of Carex macrocephala in Eastern North America with Notes on Its Co-Occurrence with Carex kobomugi in New Jersey. Journal of the Torrey Botanical Society 134 (1): 126-134.
