Eleocharis tuberculosa (Michx.) Roemer & J.A. Schultes
Habitat: Wet sandy and peaty shores and swamps. [Open wetland, not coastal nor rivershore (non-forested, wetland)]
Range: Maine to Pennsylvania, Florida and Texas, near the coast.
Aids to Identification: The long-tubercled spike-rush is an annual, grass-like plant that grows as a tuft of flower stalks standing 30-60 cm tall; the leaves are reduced to cylindrical sheaths around the base of the stalks. The inconspicuous flowers are borne in dense ovoid heads about 1 cm long, covered with brown scales. The distinguishing feature is the large size of the tubercle (large, soft, cap-like structure on top of each achene) often larger than the achene itself. The tubercles are smaller than the bodies of the achenes in other Maine species.
Ecological characteristics: Ecological relationships in Maine are not well known.
Phenology: Flowers July - September.
Synonyms: Scirpus tuberculosa Michx.
Known Distribution in Maine: This rare plant has been documented from a total of 1 town(s) in the following county(ies): Oxford.
Reason(s) for rarity: Northern limit of range.
Conservation considerations: Heavy recreational use of the sandy habitats where this occurs appears to be partly responsible for this species's decline in Maine, and may be detrimental to the remaining population.