Spiranthes bightensis M.C. Pace, 2021

Pace, Matthew C., 2021, Spiranthes bightensis (Orchidaceae), a New and Rare Cryptic Hybrid Species Endemic to the U. S. Mid-Atlantic Coast, Phytotaxa 498 (3), pp. 159-176 : 164-170

Spiranthes bightensis M.C. Pace , sp. nov.

[ancient S. cernua × S. odorata ].—

Type: U. S. A. Maryland: Worcester County, Bainbridge Park pond , Ocean Pines, off of Beaconhill Rd. , ca. 3.5 km west of Isle of Wight Bay, 23 October 2013, Pace 608 (holotype: NY , isotypes: K , US ). Fig. 3 .

Diagnosis. Spiranthes bightensis is most similar to S. cernua , from which it can be distinguished by its stoloniferous roots (vs. non-stoloniferous), typically longer and wider, more lanceolate leaves (vs. linear-lanceolate, 15–21.4 × 1.4–1.7 cm vs. 8.7–20 × 0.4–1.1 cm, Fig. 3 , 4 , Table 1 ) commonly fragrant flowers (vs. typically lacking fragrance), and slightly thickened central labellum (vs. centrally membranous). Spiranthes bightensis can be distinguished from S. odorata by its truncate column to rostellum transition zone, vs. lanceolate, and shorter and narrower leaves (15.0–21.4 × 1.4–1.7 cm vs. 13–51.7 × 1.8–2.7 cm).

To ca. 100 cm tall. Roots slender, stoloniferous. Leaves 1–5, basal, held upright, remaining until after anthesis, lanceolate, 15–21.4 cm long, 1.4–1.7 cm wide. Trichomes capitate and glandular. Spike robust, thickened, a tightly coiled spiral (appearing as 3–4 ‘ranks’), moderately to densely pubescent. Floral bracts pubescent, 11.8–22.6 mm long. Flowers campanulate, slightly nodding, white to pale ivory, lightly to strongly fragrant with a scent varying from general floral to vanilla-jasmine. Sepals moderately to densely pubescent. Dorsal sepal apically slightly to strongly recurved, concave, lanceolate, 8.3–11.7 mm long when flattened. Lateral sepals lanceolate, acute, very slightly upwardly falcate, slightly ascending, the apices often incurved, surpassing the dorsal sepal and petals, 9.2–11 mm long. Dorsal petals slightly concave, lanceolate, bluntly acute, slightly to strongly recurved at tips, with the dorsal sepal appearing stellate, 9.5–11 mm long when flattened. Labellum recurved strongly downward at about 1/3 the distance from the claw to labellum apex, centrally glabrous, upper margin entire to very slightly undulating becoming shallowly laciniate to lacerate towards the apex, centrally white to pale yellow, 7.7–12.2 mm long, 3.0– 5.5 mm wide at the area of recurvature when flattened, apex acuminate; callosities/nectar glands, white to pale yellow, conical, upright, 1–2 mm tall. Column 4.1–6 mm long, apex truncate, column foot stout; rostellum 1.2–1.5 mm long; viscidium linear, 1–1.8 mm long. Ovary moderately to densely pubescent.

Etymology: —From the Old English / Anglo-Saxon ‘ byht ’, meaning bend or bay, a bight is a shallowly curved coastline or extremely wide bay; its use here refers to the Mid-Atlantic and New York Bights, which stretches from the Nantucket Shoals off southern New England southward to Cape Lookout, North Carolina. Spiranthes bightensis is endemic to the central region of this bight. Atlantic Ladies Tresses is the suggested common name.

Distribution and Habitat:—North American Geologic Coastal Plain endemic, restricted to a narrow region of the Mid-Atlantic Bight and New York Bight from the southern Hudson River estuary and Long Island, New York, to the Delmarva Peninsula of Maryland and Virginia ( Fig. 5 ). The only documented population north of the Fall Line occurred in “bogs” and “boggy places” around Tappantown, New York. The distribution of S. bightensis bears many similarities to the “Southeastern Massachusetts to southern New Jersey and adjacent Delmarva Peninsula” endemism pattern described by Sorrie & Weakley (2001), although it is currently unknown from maritime Rhode Island or Massachusetts. Spiranthes bightensis is regionally syntopic with S. cernua , however it does not co-occur with that species, and it occurs just to northeast of the distributional limit of S. odorata . The cultivar ‘Chadds Ford’ is relatively common in cultivation.

Occurring in wet to moist, short-statured, rarely brackish, open graminoid-cyperoid meadows, maritime dune swales, Sphagnum Linneaus (1753: 1106) dominated freshwater lake and pond edges, and roadsides; occasionally/ periodically shallowly inundated. Associated species include Agalinis Rafinesque (1836: 61–65) spp. , Eutrochium Rafinesque (1836: 78) spp. , Gentiana Linneaus (1753: 227) spp. , Morella pensylvanica ( Mirbel 1804: 190) Kartesz (1999) , Nyssa sylvatica Marshall (1785: 97–98) , Phragmites australis ( Cavanilles 1799: 100–101) Trinius ex Steudel (1840: 143) , Rhexia Linnaeus (1753: 346) spp. , Solidago sempervirens Linnaeus (1753: 87) , and Symphyotrichum Nees (1832: 135–136) spp. Although the distribution of S. bightensis encompasses the Atlantic Coastal Pine Barrens ecoregion of New Jersey and Long Island, it has not been collected from classic Pine Barrens habitats such as Pinedominated forests. Rather, S. bightensis primarily occurs along the Inner Coastal Plain and Barrier Islands/Coastal Marshes ecoregions, and open wet prairie and meadow-like elements within the Cape Cod/Long Island Pine Barrens ecoregion.

Phenology: —Late September – early November.

Conservation: —Rare and highly localized, although extant populations are often robust and the cultivar ‘Chadds Ford’ is common in cultivation. Apparently never more than ca. 50 km from the Atlantic Ocean coastline, occurring at elevations under ca. 30 m. Although occasionally found in brackish habitats, this species is at major risk of inundation and saltwater intrusion from global warming induced sea-level rise. Its coastal habitat is also under immense pressure from development, urbanization, and invasive species. Poorly timed roadside mowing regimes are an additional threat, as populations are often cut just as they begin to flower, with such mowing regimes appearing to have destroyed at least one recently collected population, Zaremba 9079 (NYS), which I was unable to relocate 24 years later in 2016 along a very closely cropped highway median. It is important to note that frequent natural disturbances such as fire and hurricanes are critical to maintaining the open habitats favored by S. bightensis , and a regional decline in periodic disturbances such as fires may also contribute to the decline of this species in concert with habitat destruction and other potential stresses such as heavy metal deposition in regional soils ( Pouyat & McDonnell 1991).

Over the past 200 years, populations of S. bightensis appear to have undergone major declines possibly related to the synergistic effects of expanded urbanization and habitat destruction and degradation ( Fig 5 ). Most documented populations from urban centers such as the New York metropolitan area and Philadelphia have not been collected or otherwise observed in at least the past ca. 100–20 years, and a majority of the remaining known populations occur in less densely populated areas of central and southern New Jersey and the central Delmarva peninsula, often in parks or other protected areas. I searched for many of the historic populations that have not been observed in the past 20 years but was unsuccessful in re-locating any. In this regard, the cultivar ‘Chadds Ford’ is illuminating, as it was wildcollected and brought into cultivation from a rural Bear, Delaware, property just before the site was developed into suburban tack housing ( Glick 2001). Alarmingly, the known remaining populations of S. bightensis are also the most physically close to the ocean, and at an average elevation of 6.5 m above sea-level are more immediately threatened by climate change driven sea-level rise. Furthermore, the Northeastern Megalopolis forms a major physical barrier to inland migration. The largest contraction in distributional area occurred from 1900–1940’s, with the fragmentation of a previously essentially continuous distribution into several smaller regional and discontiguous extant meta-populations. The overall distributional area of these fragmented meta-populations seems to have stabilized from 1950 to the present, however the total number of known populations has continued to decline ( Fig. 5 ). This observed pattern does not appear related to the well-documented decline of North American herbarium collecting ( Pranther et al. 2004), as recent iNaturalist observations have partially supplemented physical herbarium vouchers, and North American Orchidaceae are rigorously documented by citizen scientists; rather, it is due to actual declines and losses of historic S. bightensis populations. The observed range-wide collapse, distributional contraction, and fragmentation of S. bightensis fits into a broader trend for Northeastern North America Orchidaceae ( Pace 2020) and other phylogenetically diverse taxa (e.g., Willis et al. 2008, Duda et al. 2020, Zattara & Aizen 2021). Based on the available data, including recent field work, S. bightensis appears be extirpated from New York state. The largest known ex-situ conservation collection of. S. bightensis is housed as the Mt. Cuba Center, in Hockessin, DE, primarily composed of accessions of the cultivar ‘Chadds Ford’.

Spiranthes bightensis — U. S. A. Delaware: Kent Co., Kenton, s.d., Thompson s.n. ( F!). Sussex Co., E side of DE 1 (Coastal Highway) , 0.5 mi. S of Assawoman Street, York Beach , 12 Oct 2013, Longbottom 20494 ( USF!). Indian River , Oak Orchard , 10 Oct 1928, Denslow s.n. ( NYS). Millsboro, Sep 1880, Canby s.n ( NY!). Maryland: Dorchester Co., SW of the town of Vienna, along Steele Neck Road at Kraft Neck Road W of the road , 9 Oct 2005, Longbottom 6897 ( PH!). Along Elliott Island Road , 7 mi S of Henry’s Crossroads Rd, Oct 14 1990, Longbottom 1332 ( USF!). Wicomico Co., Town of Pittsville, along US Rt 50, Ocean Gateway , between Friendship Road and Sixty Foot Road, in roadside ditch on N side of the road, 14 Oct 2006, Longbottom 8067 ( NCU!). Rt 50 crossing at Nanticoke River, Ferry Point , 12 Oct 1981, Hill 10866 ( AMES!, GA!, NY!). Worcester Co., Town of Ocean Pines, at Bainbridge Park , edge of pond, 12 Oct 2008, Velsir s.n. ( NY!). Campground , W of dunes and E of road, North Beach campground, National Seashore , Assateague Island , 6 Oct 1984, Hill 15994 ( MARY!). New Jersey: Atlantic Co., On branch of overhead road over PRR about one mile below station, Egg Harbor City, 20 Oct 1920, Meredith s.n. ( PH!). In marsh by bridge at Oceanville , 3 Oct 1939, Hynes 1004 ( PH!). Cape May Co., Cape May Point State Park , adjacent to the path paralleling the ocean, in-between the parking lot and the “Yellow Trail”, 175 m from the ocean, 19 Oct 2013, Pace 607 ( NY!). Gloucester Co., Along Mantua Creek, near the village of Mantua , 29 Oct 1921, Long 25369 ( PH!). Griffith’s Swamp , Oct 1865, Porter s.n. ( CHBR!). Ocean Co., Ocean Twp. , Waretown, along Waretown Creek , below Tuckerton RR, 4 Oct 1910, Long 5449. ( CHRB!, PH!). Salem Co., Boggy border swale along Game Creek , N of Biddles Landing, 3 Oct 1934, Fogg 7520 ( PH!). New York: Nassau Co., Hempstead L.I. , 2 Sep 1896, Mulford s.n. ( NY!). Suffolk Co., Brookhaven, Sunrise Highway margin near exit 59, 9 Sep 1992, Zaremba 9079 ( NYS!). Eastport , 14 Sep 1894, collector unknown ( MO!). Rockland Co., Tappantown, Sep 1861, Austin s.n. ( NY barcode 1392825!). Tappantown, Sep 1861, Austin s.n. ( NY barcode 1392828!). Tappantown, 1861, Austin s.n. ( NY barcode 1392822!). Virginia: Accomack Co., Virginia Eastern Shore, Coards Branch Pond , SW of Parksley, 11 Nov 1991, Zebryk s.n. ( GA!) .

Figures

FIGURE 3. Line drawing of S. bightensis. A. Habit and leaf detail. B. Inflorescence. C. Inflorescence detail. D. Floral bract and flower. E–M. Dissected flower. E. Dorsal sepal. F. Dorsal petal. G. Lateral sepal. H. Labellum, flattened. I. Labellum and column in natural position. J. Column, profile view. K. Column, ventral and dorsal view. L. Anther. M. Pollinia. Drawn from Austin s.n. barcode 01392822 (NY) and Pace 608 (NY) by Bobbi Angell.

FIGURE 4. Comparative line drawing of S. cernua (A, B, G–K), S. bightensis (C, D, L–O), and S. odorata E, F, P–S) labella (A–F) and leaves (G–S). A. Pehr s.n., lectotype of Ophrys cernua (LINN!). B. Pace 615 (NY!). C. Pace 607 (NY!). D. Pace 608, holotype of S. bightensis (NY!). E. Pace 611 (NY!). F. Nuttall s.n., lectotype of Neottia odorata (PH!). G. Pehr s.n., lectotype of Ophrys cernua (LINN!). H. Stone 9462 (PH!). I. Long 15163 (PH!). J. Pace 615 (NY!). K. Pace 605 (NY!). L. Pace 608 (NY!). M. Austin s.n. barcode 01392822 (NY!). N. Long 5449 (PH!). O. Pintauro 9, ‘Chadd’s Ford’ (NY!). P. Kral 62918 (SAT!). Q. Small 9284 (NY!). R. Pace 614 (NY!). S. Pace 611 (NY!). A. Drawn by A. Gray, published in Sheviak and Catling (1980), used with permission; B. & D. Drawn by Bobbi Angell, used with permission; F. Drawn by P. Catling, attached to Nuttall s.n., used with permission of Philadelphia Herbarium (PH) at The Academy of Natural Sciences of Drexel University; all others drawn by M. Pace.

FIGURE 5. Distribution map of S. bightensis, highlighting population loss over time. A. Collections made pre-1890’s–present (the hypothesized original distribution of S. bightensis). B. 1900–present. C. 1950–present. D. 2000–present. Prepared by Elizabeth Gjieli, NYBG GIS Lab.