By Barre Hellquist
Ossipee — January 7, 2006 — Ossipee Lake has been known for a number of rare plants occurring along its shores or in its immediate vicinity. The Ossipee Lake shoreline harbors many uncommon species due to its similarities to the coastal, sandy regions to the south and east.
The Rare Plant List of the New Hampshire Natural Heritage Bureau lists 10 species of plants that presently occur or have occurred historically around the lake. These include aquatic plants, shoreline plants, or plants of the nearby Ossipee Lake poor level fen/bog system.
During September 2005, the New Hampshire Natural Heritage Bureau surveyed the proposed Ossipee town beach area of Long Sands, along the south side of Ossipee Lake. They discovered two subpopulations of the state endangered grassleaf goldenrod (Fig. 1) Euthamia caroliniana Greene ex Porter & Britt. (Solidago tenuifolia Pursh) within the proposed beach study area.
A third subpopulation was found immediately west of the proposed beach area. They noted that other populations also had been documented along the contiguous beach to the southwest. In 1971, Hellquist documented the grassleaf goldenrod along Long Sands Beach at the south end of the Lake. He also found it growing on the beaches near the mouths of the Pine River and Bearcamp River.
Plants in the genus Euthamia were originally included in the goldenrod genus Solidago. A careful study of the goldenrods showed that the flat-topped species should be recognized as a new genus (Euthamia).
Ossipee Lake also has the more common and widespread narrow-leaved goldenrod (Fig. 2), Euthamia graminifolia (L.) Nutt. ex Cass., growing on the same beaches as E. caroliniana. These are easily separated by the number of veins in the leaves, one in E. caroliniana and three in E. graminifolia.
The range of E. caroliniana is along the coastal plain from Nova Scotia south throughout New England, to Florida and west to Louisiana. It also occurs inland in southern Michigan and northern Indiana. Throughout its range, the grassleaf goldenrod is listed as G5 (species widespread, abundant, and secure globally). In New England, it is listed as S2 in Maine (imperiled because of rarity and vulnerability to further decline) and S1 in New Hampshire (critically imperiled because of extreme rarity).
There are six locations for E. caroliniana in New Hampshire and three recent populations in Maine. The Maine locations are all from southwestern Maine, near Ossipee Lake.
The Long Sands area of Ossipee Lake is well known for providing important habitat for the coastal disjunct flora of the lake. Euthamia caroliniana was relatively common in the 1970s on Long Sands. During this time Long Sands had open sandy areas interspersed with raised peat mats immediately along the shoreline.
In the 1970s, water levels of Ossipee Lake were allowed to drop during the summer and the peat mats would often be out of the water. Over the years the lake levels have been kept higher. The peat mats have disappeared along with a number of the uncommon or rare plants of the south shore.
Some of these include: appressed bog club-moss, Lycopodiella appressa (Chapm.) Cranfill; comb-leaved mermaidweed, Proserpinaca pectinata Lam; Virginia meadow-beauty, Rhexia virginica L; and the twisted yellow-eyed grass, Xyris torta Sm.
Back from the shoreline on the sandy beaches, the rare hairy Hudsonia, or beach-heather Hudsonia tomentosa, occurs. Two subpopulations of this species were located within the proposed beach area.
The absence of these plants in recent years may be due to the higher water levels and the subsequent pounding of waves throughout the summer. The increased use of the beach over the years also probably has contributed to the change in the shoreline. These species and natural areas will remain in peril unless all efforts are taken to preserve them.