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2013 THE MICHIGAN BOTANIST 25
REDISCOVERY OF RHYNCHOSPORA (PSILOCARYA) NITENS (CYPERACEAE) IN INDIANA
Roger L. Hedge Emily J. Stork
Indiana Department of Natural Resources Indiana Department of Natural Resources Division of Nature Preserves Division of Nature Preserves 402 W. Washington Street, Rm W267 5690 Chase St. Indianapolis, IN 46204 Merrillville, IN 46410 firstname.lastname@example.org email@example.com
In 2012 the authors rediscovered Rhynchospora (Psilocarya) nitens in Porter County at its only known site of occurrence in Indiana, providing the first documentation of the species for the site and the state in over 50 years. Prior to the 2012 discovery, the species had been collected in the state only twice since 1899. An Atlantic and Gulf Coastal Plain disjunct, this sedge is represented by only two occurrences in the Great Lakes region: Allegan County, Michigan and Porter County, Indiana.
Rhynchospora nitens (Vahl) A. Gray is an Atlantic and Gulf Coastal Plain sedge that ranges in the U.S. from Texas to Massachusetts and that has disjunct occurrences in Indiana and Michigan. Farther south it occurs in the West Indies and Central America (Kral 2002). In the Atlantic Coastal Plain states in the U.S. the species is listed as “vulnerable” to “critically imperiled” in 8 of the 14 states where it occurs, namely Texas, Georgia, North Carolina, Delaware, Maryland, New Jersey, New York, and Massachusetts, and as “possibly extirpated” in Vir- ginia (NatureServe 2014). It is listed as “apparently secure” in Louisiana and Mississippi (NatureServe 2014). Although NatureServe (2014) indicates that the species has not been ranked or is still under review in Alabama, Florida, South Carolina, and Michigan Rothrock (2009) states it is “deemed secure from extir- pation in Florida and Mississippi” and Reznicek (1999) notes that it is primarily a southern coastal plain plant that is very rare in the northern parts of its range.
In the Great Lakes region, R. nitens was known only from Porter County, In- diana, until its discovery in 1999 in Allegan County, Michigan (Reznicek 1999). The Michigan record represented the only extant occurrence in the Great Lakes region at the time of its discovery, since the species was considered long extir- pated in Indiana (Indiana Natural Heritage Data Center 2013). On September 27, 2012, however, the authors found R. nitens while conducting a botanical survey of wetlands in the Dune Acres Unit of the Indiana Dunes National Lakeshore in Porter County, Indiana.
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Rhynchospora nitens is strikingly similar to R. scirpoides (Torr.) Griseb. As noted by Reznicek (1999), R. nitens has a greyish cast to the spikelets in contrast to the brown spikelets of R. scirpoides. The grey spikelet color in R. nitens is due to the scale apices possessing wider hyaline margins (Figure 1). Although this character may be helpful in searching for this species in the field, it can be very subtle. The achene body of R. nitens has a pronounced cross rugulose pattern, whereas the achenes of R. scirpoides are smooth to only slightly rough. Reznicek (1999) also notes that the nearly mature achenes of R. scirpoides have a con- spicuous pale border that is lacking in those of R. nitens. The tubercles, however, are quite diagnostic and easily separate the two species. In R. nitens the tubercle is noticeably short (less than 0.5 mm), crescent-shaped, and distinctly wider than tall. The tubercle of R. scirpoides is at least as tall or taller than wide (0.5 mm or greater) and triangular (Figure 2). Reznicek (1999) also states that the longer tu- bercle of R. scirpoides gradually tapers “into the more or less persistent style”, whereas that of R. nitens is deciduous. Rhynchospora scirpoides is a state-threat- ened species in Indiana (Indiana Natural Heritage Data Center 2013). Rhyn- chospora nitens and R. scirpoides, along with the primarily tropical R. eximia (Nees) Boeck., are annual species that were formerly included in the genus Psilocarya. They can be separated from other Rhynchospora species by their lack of perianth bristles and the presence of several achenes per spikelet
FIGURE 1. Spikelets of Rhynchospora nitens. Photo by Emily J. Stork.
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FIGURE 2. Achenes of Rhynchospora scirpoides (the 2 achenes on the left with longer tubercles) and R. nitens (the 2 achenes on the right with short tubercles). Photo by John Maxwell.
(Rothrock 2009). Rhynchospora nitens and R. scirpoides superficially resemble Fimbristylis autumnalis (L.) Roem. & Schult. and are typical associates of that species in the field. In contrast to the two Rhynchospora species, F. autumnalis has achenes that lack distinct tubercles and is generally a smaller plant overall, having smaller inflorescences and spikelets (Rothrock 2009).
LOCATIONS AND HABITAT
The general area of all known historical records of Rhynchospora nitens in Indiana is within approximately one mile of Lake Michigan near the common boundary of the Portage and Dune Acres USGS quadrangles in the Lake Michi- gan Border Section of the Northwestern Morainal Natural Region (Homoya et al. 1985). In the broader context, this area lies within the Eastern Broadleaf For- est (Continental) Province (Bailey 1995). Our 2012 discovery is approximately 1300 meters east of historic Goose Lake where some earlier collections were made. Dune Park, also mentioned as an early collecting site for this species, was farther west, approximately two miles beyond Goose Lake. It is possible that
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FIGURE 3. Dry lake bed of Little Lake, one of the locations where Rhynchospora nitens was found. The plants were in the vegetation on the left side of photo. Photo by Emily J. Stork.
some botanists may have ascribed this name to the general area that includes Goose Lake, since they contained similar wetland communities (Pavlovic, pers. comm.). Dune Park was also the site of an historic train stop along the Chicago South Shore and South Bend Railroad in the Indiana Dunes, and it, along with Goose Lake, has long been lost to industrial development.
The extant wetlands occupied by R. nitens are shallow and relatively flat-bot- tomed with sandy and peaty substrates (Figure 3). These features align closely with those ascribed to the Michigan site by Reznicek (1999). When water levels are low, such wetlands may support a diverse flora that includes a variety of an- nuals and short-lived perennials, many of which are Atlantic and Gulf Coastal Plain disjuncts. In addition to Rhynchospora nitens, other rare coastal plain species known or previously reported from the area include Ludwigia sphaero- carpa Elliott, Rhynchospora macrostachya Torr. Ex A. Gray, Rhynchospora scir- poides (Torr.) Griseb., Scleria reticularis Michx., Schoenoplectus purshianus (Fernald) M. T. Strong, Juncus pelocarpus, Juncus scirpoides Lam., Panicum verrucosum Muhl., Polygonella articulata (L.) Meisn., Utricularia purpurea Walter, Eleocharis melanocarpa Torr., and Fuirena pumila (Torr.) Spreng. (Reznicek 1994, Lamerson 1950, Indiana Natural Heritage Data Center 2013). Many of the species persist in permanent seed banks and germinate when water levels drop and mud and sand flats are exposed (Keddy and Reznicek 1982).
Indiana experienced widespread heat and drought in 2012, and the wetlands
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FIGURE 4. Site (referred to in the text as “unnamed wetland”) where Rhynchospora nitens was first found in 2012. Photo by Emily J. Stork.
surveyed in the target area were completely dry with the exception of a single, small ponded area. On September 27, 2012, a locally abundant population of R. scirpoides was closely scrutinized, revealing a single clump of R. nitens in a small unnamed wetland just north of Little Lake (Figure 4). On October 2, addi- tional plants, perhaps hundreds were found in this small wetland and Little Lake. Rhynchospora nitens associates included Rhynchospora scirpoides, Rhyn- chospora macrostachya A. Gray, Panicum verrucosum Muhl., Scleria reticularis Michx., Dichanthelium spretum (Schult.) Freckmann, Dulichium arundinaceum (L.) Britton, Fimbristylis autumnalis, Hypericum boreale (Britton) E. P. Bick- nell, Proserpinaca palustris L., Eupatorium serotinum Michx., and Cephalan- thus occidentalis L. These wetlands also contain stands of the non-native inva- sive grass Phragmites australis (Cav.) Steud. Further encroachment of this species and Cephalanthus occidentalis potentially threatens R. nitens and asso- ciated coastal plain flora. Following this discovery, although additional sites be- lieved to have potential for R. nitens were checked elsewhere in Porter County as well as in Elkhart, Jasper, and St. Joseph counties, Indiana, no additional pop- ulations of R. nitens were found.
NOTES ON HISTORIC RECORDS
The earliest collections of Rhynchospora nitens in Indiana and the Great Lakes region appear to have been on October 20, 1897 in Porter County by
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Agnes Chase and E. J. Hill. Although Hill’s collections were from Dune Park and/or Goose Pond [Lake] and Chase’s reads “Northwest of Porter,” these loca- tions likely pertain to the same general area, and it seems plausible that the two botanists were together on that date. The greatest number of collections ever taken in Indiana was in 1898, and all were from the same area(s) described above on the respective dates August 4 (Hill), August 18 (A. Chase, Hill), Au- gust 29 (Hill), and September 19 (Virginius H. Chase). A single collection was made in 1899 on September 12 by L. M. Umbach, also from Dune Park, in a habitat described as “slough.” This collection had been believed to have been the last time the species was seen in Indiana (Deam 1940; Swink and Wilhelm 1994; Rothrock 2009).
However, following our 2012 discovery, the authors learned about two addi- tional unpublished records of R. nitens in Indiana, both taken in the twentieth century and from the same location as the records referenced above from the late 1800s. On August 8, 1953, F. A. Swink unknowingly collected a single specimen of R. nitens. This specimen attached to the same collection sheet as a specimen of R. scirpoides is at the Field Museum herbarium in Chicago (F). The label on the sheet reads “Porter Co.: In moist open ground near Goose Lake NW of Bai- leytown” (Niezgoda, pers. comm.). This specimen was annotated by A. A. Reznicek in 2002 as R. nitens (Reznicek, pers. comm.). Another collection was made on “wet ground on border of Mud [Goose] Lake marsh, Baileytown, Porter County” on September 19, 1959 by H. R. Bennett (ILL) and indentified on the label as Fimbristylis caroliniana (Lambert) Fernald forma pycnostachya Fer- nald. It was annotated by R. Kral in 1967 as Psilocarya [Rhynchospora] nitens (Phillippe, pers. comm.).
Although the authors did not examine any additional collections of Rhyn- chospora nitens, personnel from the following herbaria were contacted regard- ing this species’ occurrence in Indiana: BUT, F, GH, ILL, ILLS, IND, MICH, MO, MOR, NY, PUL, US, and WIS. Herbarium abbreviations are those of Holmgren et al. (1990). All known Indiana collections of R. nitens are cited below. All collections are from Porter County, Indiana. Note that E. J. Hill some- times assigned the same collection number to specimens collected on different dates during the same year.
INDIANA: PORTER CO. Northwest of Porter, drying slough, 20 Oct 1897, Agnes Chase 686 (ILL – 2 sheets); Goose Pond or Dune Park, wet or damp sands, 20 Oct 1897, E. J. Hill 195, 1897 (GH, ILL); 4 Aug 1898, E. J. Hill 154, 1898 (ILL); 18 Aug 1898, Agnes Chase 920 (F, ILL – 2 sheets, MICH, US), E. J. Hill 154(2), 1898 (F – 2 sheets [2nd sheet an apparent du- plicate, but lacks a collection number and has habitat information as sand], ILL); 18, 29 Aug 1898, E. J. Hill 154, 1898 (GH). [Note 2 separate dates as per label on sheet]; 29 Aug 1898,
E. J. Hill 154(3) 98 (F), E.J. Hill 154, 1898 (ILL); East of Dune Park, sandy swamp, 19 Sept 1898, Virginius H. Chase 292 (ILL); Dune Park, slough, 12 Sept 1899, L. M. Umbach s.n. (F, GH, IND, NY, US, WIS); Near Goose Lake NW of Baileytown, moist open ground, 8 Aug 1953, Floyd A. Swink 2542 (F); On border of Mud [Goose] Lake marsh, Baileytown, wet Page 31 2013 THE MICHIGAN BOTANIST 31
ground, 19 Sept 1959, H. R. Bennett 6940 (ILL); Dune Acres Unit, Indiana Dunes National Lakeshore, at unnamed wetland, N . of NE . of NW . of SW . of Section 22, T 37N, R6W, 1-10 plants growing in sand flat with Rhynchospora scirpoides, Scleria reticularis, Dulichium arundinaceum, Proserpinaca palustris, Dichanthelium spretum, Hypericum bore- ale, Panicum verrucosum, Rhynchospora macrostachya, Fimbristylis autumnalis, Cephalan- thus occidentalis, Eupatorium serotinum, 27 Sept 2012, R L. Hedge & E. Stork 12-09-27- 101(F, Hedge personal collection), 2 Oct 2012, R L. Hedge et al. 12-10-02-127 (NY, WIS); At Little Lake, 101-1000 plants estimated growing in sand flat with Rhynchospora scir- poides, Rhynchospora macrostachya, Panicum verrucosum, Fimbristylis autumnalis, Cepha- lanthus occidentalis, 2 Oct 2012, R L. Hedge et al. 12-10-02-135 (MO, MOR, MICH).
The authors especially wish to thank Mike Homoya, Noel Pavlovic, and Tony Reznicek for their encouragement and critical review of the manuscript of this paper. For field assistance, we thank Dan Mason, Derek Nimetz, and Noel Pavlovic. We also thank Ron Hellmich for office assistance and John Maxwell for photographing the achenes. Last, but certainly not least, we are grateful for the very helpful staff at the herbaria listed above.
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