Nitellopsis obtusa, Starry Stonewort

A Non-Native Submerged Aquatic Lower

STARRY STONEWORT (SSW)

• Some information provided in this power point presentation comes from the following source:

HACKETT, R. A., CARON, J. J., & A. F. MONFILS. 2014. Status and Strategy for Starry Stonewort [Nitellopsis obtusa (N. A. Desvaux) J. Groves] Management. Michigan Department of Environmental Quality, Lansing, Michigan.

STARRY STONEWORT (SSW) Nitellopsis obtusa General Characteristics

• SSW is a nonindigenous submerged aquatic lower plant.

• SSW is a summer annual, but can overwinter as a perennial during mild winters. However, SSW in Michigan appears to thrive in the cooler waters of fall, winter, & spring, & become dormant or less active during hottest parts of summer (Pullman & Crawford 2010)

• SSW is a member of the Characeae plant family. Complete taxonomic classification will be presented.

• SSW is a filamentous alga. It has straight branches arranged in whorls of 4 to 6 long branchlets, and attached at acute angles to stem nodes.

STARRY STONEWORT (SSW) Nitellopsis obtusa General Characteristics

• Most stem & branch cells are around 1 mm in diameter, and stems can extend up to 80 cm long, or 31.5 inches (Hargeby 1990). Growth up to 2 meters (6.5 ft) has been observed at a depth of 9 m (29.5 ft) in one Michigan Lake (Pullman and Crawford, 2010). Source: www.seagrant.sunysb.edu. SSW

STARRY STONEWORT (SSW) Nitellopsis obtusa General Characteristics

• The “squeeze test” may be used to distinguish SSW from spp. In SSW, the protoplasm will pop out of the cell when squeezed. The remaining cell wall becomes limp straw (G. Douglas Pullman, Aquest Corp, personal communication). In Chara spp., the protoplasm does not separate easily from the cell wall (Hackett et al. 2014).

STARRY STONEWORT (SSW) Nitellopsis obtusa General Characteristics

• SSW has colorless hair-like filaments called rhizoids that act like roots. The rhizoids attach the plant to an aquatic bottom, but they frequently detach from an aquatic bottom to form a floating mat.

• Stoneworts have ability to absorb nutrients through all surfaces, not just the rhizoids.

• SSW can be found at depths of 3-20 feet in lakes or slow moving rivers.

STARRY STONEWORT (SSW) Nitellopsis obtusa General Characteristics

• SSW can form gyrogonites, which are calcified, spiral-shaped fructifications (Bharathan 1983, 1987). Another definition from the online plain text English dictionary is the petrified fruit of Chara hispida, a species of stonewort. Source: www.researchgate.net, shows SEM lateral & apical views of gyrogonites of Chara aspera (figs. 1-2); C. hispida (figs. 3-4); & C. globularis (figs. 5-6). STARRY STONEWORT (SSW) Taxonomic Classification • EMPIRE…………………………………………….…Eukaryota • KINGDOM…………………………………………....Plantae • PHYLUM…………………………………………..... • CLASS……………………………………….……… • ORDER……………………………………………… • FAMILY………………………………………………Characeae • GENUS……………………………………………….Nitellopsis* • SPECIES…………………………………………….obtusa *Other genera in Characeae family are Chara, Lamprothamnium Lynchnothamnus, , & Tolypella. Source: Lewis & McCount (2004)

STARRY STONEWORT (SSW) Nitellopsis obtusa General Life Cycle

• SSW plants are dioecious.

• SSW has orange female structures called oogonia that are located in the nodes of upper branchlets.

• Dark red to orange-colored oospores are female gametocytes and occur at the nodes of branches.

Source: www.wolverinelake.com. A decade of starry stonewort in Michigan ( Pullman, G. D. & G. C. Crawford, 2010). Note dark red-colored oospores. They are female gametocytes from which an egg develops. STARRY STONEWORT (SSW) Nitellopsis obtusa General Life Cycle

• In sexual reproduction, plasmogamy (fusion of haploid gametes) is followed by karyogamy (nuclear fusion) to form a diploid zygote (Graham, L. E., & L. W. Wilcox. 1999).

• Sexual reproduction in SSW occurs through production & fertilization of oospores. Mature oospores usually are produced only under eutrophic conditions & have a mandatory dormant period before germination (Bharathan 1987; Hackett et al 2014).

• Spore production may be controlled by light & tends to take place from July to September. STARRY STONEWORT (SSW) Nitellopsis obtusa General Life Cycle

• Asexual reproduction is a means by which an individual organism can produce additional copies of itself without unions of cytoplasmic nuclear materials or meiosis.

• One way SSW asexual reproduction occurs is by prolific production of vegetative bulbils. Creamy white bulbils may occur at the base of the main stem just below the substrate water interface, and on branches of the main axis at nodes.

STARRY STONEWORT (SSW) Nitellopsis obtusa General Life Cycle

• Bulbils stay viable for several years. They can be found at any point during the year, but are most abundant in late fall & early spring (Hackett et al 2014).

• Bulbils can sprout in 3-5 days under the right conditions (Bharathan 1987). STARRY STONEWORT (SSW) Nitellopsis obtusa Life Cycle With Zygotic Meiosis Most chlorophyceans & charophytes (includes Chara spp., & Nitellopsis obtusa) are primarily found in freshwaters. These algae have haploid vegetative phases, the zygote is the only diploid stage, & zygotic meiosis occurs. [After L. E. Graham & L. W. Wilcox. 1999.] STARRY STONEWORT (SSW) Nitellopsis obtusa Means of Spread of SSW

• SSW can be spread by oocytes. Oocytes could be easily transported in aquatic plant debris caught in boat trailers. Also oocytes can easily become attached to the fur and feathers of aquatic fauna, & is an effective Aquatic plants hitching ride on a boat way for SSW to spread trailer. Michigan Dept. of Environmental rapidly among inland lakes Quality. MSU Extension. Online photo (Pullman & Crawford msue.anr.msu.edu 2010).

STARRY STONEWORT (SSW) Nitellopsis obtusa Means of Spread of SSW

• SSW is easily fragmented & these fragments may act as disseminules that could be important in the spread of the plant within a lake & from lake to lake. Boat traffic can cause significant fragmentation of SSW that can float on the water surface & create nuisance conditions on leeward shorelines (Pullman & Crawford 2010). STARRY STONEWORT (SSW) Nitellopsis obtusa Means of Spread of SSW

• SSW can be spread by star-shaped bulbits that occur mainly on the lower stem nodes near the substrate, reach 4 mm across (0.2 in), & stay viable for several years (Hackett et al 2014).

Source: Online photo at www. uwsp.edu SSW bulbits & filamentous branches.

Source: www.masoncounty press.com. SSW plants invades Pentwater Lake. STARRY STONEWORT (SSW) Nitellopsis obtusa Means of Spread of SSW • Others vectors that likely are involved in the spread of SSW include aquatic fauna, ballast water, boats, and trailers. SSW was believed to have been introduced in ship ballast water into the St. Lawrence Seaway (Geis 1981; Schloesser 1986).

• Little data have been published regarding ideal environmental conditions or nutrient levels that promote invasive SSW growth in lake ecosystems (Brown 2014). Most of what is known comes from observations (Hackett et al 2014). STARRY STONEWORT (SSW) Nitellopsis obtusa Distribution Native Range: SSW is native to Eurasia, from the west coast of Europe to Japan (Mills et al. 1993; Soulie-Narsche et al. 2002). Present: United States range includes much of the Great Lakes Region, & parts of the Upper Mississippi-Crow-Rum Basin, the Rock Basin, the Upper Illinois Basin, the Allegheny Basin, the Upper Susquehanna Basin, & the St. Francois River Basin (U. S. Dept. of the Interior, U. S. Geological Survey. URL:nas.er.usgs.gov.). This website actually lists collection information for 1529 SSW sites in the Great Lakes Region.

STARRY STONEWORT (SSW) Nitellopsis obtusa Distribution Present Range in the Great Lakes Region includes: Michigan: 1st found in 1983 at Lake St. Clair, along the Saint Clair & Detroit Rivers (Schloesser et al. 1986). Now occurs at lakes in all Lower Peninsula basins & the Millecoquins Lake of the Upper Peninsula (Pullman & Crawford 2010). Michigan has most reported occurrences of any state.

Indiana: Initially discovered in 2008 in Lake Wawasee (Edgell 2011; Aquatic Weed Control 2015). Currently SSW is in 8 lakes in northeastern Indiana (Edgell 2011; Pearson 2015).

STARRY STONEWORT (SSW) Nitellopsis obtusa Indiana Distribution (USGS Data) Indiana: Currently SSW is in 10 lakes in northeastern Indiana as follows: Kosciusko Lake Wawasee, Syracuse 2008 Established Kosciusko Syracuse Lake, Syracuse 2011 Established Kosciusko Tippecanoe Lake, Oswego 2013 Established Kosciusko Webster Lake, North Webster 2015 Established LaGrange Adams Lake, Wolcottville 2014 Established LaGrange Wall Lake near town of Orland 2010 Established Steuben Crooked Lake, Angola 2011 Established Steuben Jimmerson Lake, Angola 2012 Established Steuben Lake George at Ind/MI border 2009 Established Steuben Lake Pleasant* 2015 Established

*just behind boat launch in end of channel by the marina

STARRY STONEWORT (SSW) Nitellopsis obtusa Distribution (USGS Data)

NOTE: These data are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science. The data have not received final approval by the U. S. Geological Survey (USGS) and are provided on the condition that neither the USGS nor the U. S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data.

STARRY STONEWORT (SSW) Nitellopsis obtusa Distribution Present Range in the Great Lakes Region includes:

Minnesota: Only two known occurrences, both in 2015 at Mud Lake & Lake Koronis (MN DNR 2015).

New York: First spotted in North America in 1978 along the St. Lawrence River (Geis et al. 1981; Mills et al. 1993) & later in 1981 at Lake Ontario. Since 2005, SSW found at Oneida, Chautauqua, Otisco, Otsego, & Cayuga Lakes (MapInvasives 2015).

Pennsylvania: Only occurrence was at Presque Isle Bay near Erie; 1st seen in 2009 & confirmed in 2012 (Jim Grazio, PA DEP., pers. comm, 2015).

STARRY STONEWORT (SSW) Nitellopsis obtusa Distribution Present Range in the Great Lakes Region includes:

Vermont: Discovered in 2015 in a small cove at southeastern Lake Memphremagog (Flow 2015).

Wisconsin: Found in 2014 at Little Muskego Lake (WI DNR 2014). Additional SSW was spotted in 2015 at Silver, Long, Pike, Big Muskego, & Bass Bay Lakes (WI DNR 2015). STARRY STONEWORT (SSW) Nitellopsis obtusa Ecological Impacts of SSW • SSW reduces the diversity of plants. It is an aggressive aquatic lower plant that is able to out-compete all other Michigan aquatic plant species, including all invasive species & current alien species (Hackett et al 2014). SSW can alter or eliminate native submerged aquatic plants.

• SSW can form dense mats that act as benthic barriers accumulating phytotoxins & making sediments inhospitable for plant growth (Pullman & Crawford 2010).

STARRY STONEWORT (SSW) Nitellopsis obtusa Ecological Impacts of SSW

• SSW mats have been observed to negatively affect fish reproduction behavior by compromising nesting & feeding habitat (Hackett et al 2014). Dense mats of SSW directly impact the habitat used by native fish for spawning. Bass and sunfish are known to regularly spawn in dense growth of native Chara species, but these spawning behaviors did not occur in correspondingly dense growths of SSW (Pullman & Crawford 2010). STARRY STONEWORT (SSW) Nitellopsis obtusa Management of SSW • Prevention - Preventing the establishment of SSW is preferable to post- establishment management. In Michigan, SSW may neither be sold nor grown in the state under the Natural Resources & Environment Protection Act 451 of 1994 (Hackett et al 2014).

- Some actions that may prevent & limit the dispersal on SSW include providing boat washing stations for high-traffic public lake accesses, & developing & sustaining a water recreation vehicle & trailer inspection program (Hackett et al 2014).

STARRY STONEWORT (SSW) Nitellopsis obtusa Management of SSW

• Biological (Pullman & Crawford 2010). -There are no known biological controls for SSW.

STARRY STONEWORT (SSW)

Nitellopsis obtusa

• Mechanical Management of SSW - Mechanical harvesting of SSW is difficult because its dense growth quickly fills harvesters, & recolonization is fast if adjacent population remain (Pullman & Crawford 2010). Also such harvesting may leave fragments which can re-root & spread Source: www.mlive.com. LEONI, MI. In an effect to cut down on the use of chemicals in Center Lake, the Clearwater Lake infestation. Assoc. began using a different method for clearing aquatic plants.

STARRY STONEWORT (SSW) Nitellopsis obtusa Management of SSW • Management – Chemical (Pullman & Crawford 2010) -SSW is highly sensitive to copper & endothall chemical treatments, but no treatments have been developed for complete lake eradication (Hackett et al 2014). If SSW is growing in a dense mat, only the top layer will die back with a standard treatment.

-Chemical treatments mixed with chelating agents may also be used to treat deeper into the mats (Pullman & Crawford 2010).

-More research is needed to determine better chemical treatments to control SSW. (Clemson Univ. & Dr. Nate Bosch)

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2008- SSW was first observed in summer 2008 on Lake Wawasee in the channels west side of Johnson Bay.

• 2009 (August)- Treatment of 15 acres in Johnson’s Bay using Nautique herbicide for control of SSW.

• 2010- Treatment of 20 acres in Johnson’s Bay using Nautique herbicide at 0.8 ppm for control of SSW.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake

• NAUTIQUE is an aquatic herbicide. The active ingredients are [1] Copper Ethylenediamine Complex (Case# 13426-91-0) at 13.2%, [2] Copper Triethanolamine Complex (Case# 82027-59-6) at 14.9%, and [3] Other Ingredients at 71.9%. Metallic copper equivalent equals 9.1%. Signal word is danger.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2011- Three small test areas in Johnson’s Bay were treated with varying rates & formulations of Cutrine Ultra & Hydrothol herbicides. It was determined from these tests that using Cutrine Ultra at the rate of 2.4 gal per acre-foot in combination with Hydrothol 191 at the rate of 1 quart per surface acre was the most effective treatment. On September 16, 2011, 4 areas in Johnson’s Bay were treated with this new herbicide prescription.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • CUTRINE-ULTRA is a algaecide/herbicide/cyanobactericide. The active ingredients are [1] Copper Ethanolamine Complex, Mixed at 27.8%, and [2] Other Ingredients at 72.2%. Contains 0.9 lbs. of elemental copper per gallon. Metallic copper equivalent, 9%. Signal word is danger.

• HYDROTHOL 191 is an aquatic algaecide and herbicide. The active ingredients are [1] Mono(N,N-dimethylalkylamine) salt of endothall at 53.0%, and [2] Other Ingredients at 47.0%. Contains 2 lbs. endothall acid per gallon. Signal word is danger.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2011- SSW was first discovered in Syracuse Lake in the 4.5 acre access channel adjacent to Syracuse Henry Ward Park.

• 2011- IDNR receives grant through Great Lake Restoration Initiative for control of exotic aquatic plant species. Since 2011, the IDNR has fully funded numerous SSW treatments on both Lake Wawasee & Syracuse Lake. These treatments have ranged from 11.29 acres to 67.39 acres & have used a combination of Cutrine Ultra herbicide at the rate of 2.4 gal per acre foot with Hydrothol 191 herbicide at various rates to control SSW.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2009-2012- See summary table sheets 7 & 8 in “Aquatic Vegetative Management Plan 2012 Update Lake Wawasee & Syracuse Lake” for documentation of EWM & SSW treatments in these lakes from 2007 through 2012.

• 2014- On 6-4-2014, total surface acres of SSW in Syracuse Lake was estimated to be 48.22 acres.

2014 SYRACUSE LAKE SSW DISTRIBUTION STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2014- On 7-10-2014, Aquatic Weed Control treated 17.49 acres of Syracuse Lake with Cutrine Ultra at 2.4 gal per acre foot in combination with hydrothol herbicide.

• 2014- On 8-5-2014, repeated treatments at Syracuse Lake using same herbicides & rates. These treatments funded through the Great Lakes Restoration Initiative (GLR). Cost for SSW treatments in 2014 was $787.47 per 10 acre-feet treated.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2014- On 7-(9 & 11)-2014, Aquatic Weed Control treated 113.4 acres of Lake Wawasee SSW with Cutrine Ultra at 2.4 gal per acre-foot in combination with hydrothol herbicide.

• 2014- On 8-5&6-2014, repeated treatments at Lake Wawasee using same herbicides & rates. Areas 9,11,14,21,27,28,29 on Lake Wawasee were not treated. Also the North West area in section 12 was not treated. These treatments funded through the Great Lakes Restoration initiative (GLRI). Cost for SSW treatments in 2014 was $787.47 per 10 acre-feet treated.

2014 LAKE WAWASEE SSW DISTRIBUTION STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2015- There was a total of 223.73 acres of SSW in Lake Wawasee along with many new open water sites, which represents 7.31% of the total acreage (3060 acres). Some 108.6 acres were treated.

2015 LAKE WAWASEE SSW DISTRIBUTION STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2015- There is a total of 48.22 acres of SSW in Syracuse Lake & it is common to most of the littoral zone of the lake. This acreage represents 11.65% of the total acreage of 414 acres.

• 2015- On 7-1-2015, a total of 17.98 acres of SSW infestation in Syracuse Lake was treated with Cutrine Ultra at the rate of 2.4 gal per acre foot in combination with Hydrothol herbicide. This acreage includes all areas of the “Syracuse Lake 2015 SSW Treatment map”.

STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2015- On 8-4-2015, a total of 8.58 acres of SSW infestation in Syracuse Lake was treated with Cutrine Ultra at the rate of 2.4 gal per acre foot in combination with Hydrothol herbicide. This treatment comprised of areas 1,5,&7 on the Syracuse Lake 2015 SSW treatment map. All SSW treatments in 2015 were funded through the Great Lakes Restoration Initiative (GLRI).

• 2015- Thus a total of 26.56 acres (17.98 + 8.58) was treated in Syracuse Lake in 2015.

2015 SYRACUSE LAKE SSW LOCATIONS STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2016- On 6-13-2016, there was a total of 233.99 acres of SSW in Lake Wawasee, which represents 7.65 % of the total acreage of 3060 acres.

• 2016- On 7-11-2016, some 108.44 acres were treated.

2016 LAKE WAWASEE AREAS TREATED ON 7-11-2016 STARRY STONEWORT (SSW) Nitellopsis obtusa History & Management Efforts Lake Wawasee & Syracuse Lake • 2016- In spring of 2016 (6-8-2016), there was a total of 210.07 acres of SSW in Syracuse Lake, which represents 50.74 % of the total acreage of 414 acres. Some 8.51 acres were treated.

2016 SYRACUSE LAKE SSW DISTRIBUTION

2016 SYRACUSE LAKE SSW DISTRIBUTION LAKE WAWASEE SSW SURFACE ACRES WITH SSW

250 233.99 223.73

200 198.86 180.7 159 150

100

56 50

15 20

NUMBER OF SURFACE ACRES WITH SSWACRES OF SURFACE NUMBER 0 0 2008 2009 2010 2011 2012 2013 2014 2015 2016

YEAR LAKE WAWASEE SSW PERCENT OF 3060 LAKE ACREAGE

8 7.65 7.31

7 6.5

6 5.91

5.2 5

4

3 PERCENT OF TOTAL LAKE ACREAGE LAKE TOTAL OF PERCENT

2 1.83

1 0.65 0.49

0 0 2008 2009 2010 2011 2012 2013 2014 2015 2016 YEAR LAKE WAWASEE SSW SURFACE ACRES WITH SSW & ACRES TREATED

250 200 150

100 50 0 2008 2009 2010 2011 2012 2013 2014 2015 2016

YEAR NUMBER OF ACRES SSW NUMBER SURFACE SSW SURFACE ACRES SSW ACRES TREATED LAKE WAWASEE SSW X AXIS SSW SURFACE ACRES % OF LAKE SURFACE ACREAGE Y AXIS SSW ACRES TREATED YEAR SSW* (PERCENT OF 3060 ACRES) ACRES TREAT 2008 0 0 0 0 2009 15 0.49 20 15 2010 20 0.65 40 20 2011 56 1.83 60 56 2012 159 5.2 80 67.39 2013 180.7 5.91 100 135.5 2014 198.86 6.5 120 113.4 2015 223.73 7.31 140 108.6 2016 233.99 7.65 160 108.44 SYRACUSE LAKE SSW SURFACE ACRES WITH SSW 250

210.07 200

150

100 NUMBER OF SURFACE ACRES

50 48.22 48.22

13.21 4.5 7.5 0 2011 2012 2013 2014 2015 2016 YEAR SYRACUSE LAKE SSW PERCENT OF 414 SURFACE LAKE ACREAGE 60

50.74 50

40

30

20

11.65 11.65

PERCENTOFTOTAL LAKE ACREAGE WITHSSW 10

3.19 1.09 1.81 0 2011 2012 2013 2014 2015 2016 YEAR SYRACUSE LAKE SSW SURFACE ACRES WITH SSW & ACRES TREATED

250

200

150

100 NUMBER OF SSW SURFACE ACRES 50

0 2011 2012 2013 2014 2015 2016 YEAR

SSW SURFACE ACRES SSW ACRES TREATED SYRACUSE LAKE SSW

X AXIS SSW SURFACE ACRES % TOTAL LAKE SURFACEACRES Y AXIS SSW ACRES YEAR SSW (% 414 SUFACE ACRES) ACRES ACRES TREAT 2011 4.5 1.09 4.5 4.5 2012 7.5 1.81 7.5 7.5 2013 13.21 3.19 13.21 10 2014 48.22 11.65 48.22 17.5 2015 48.22 11.65 48.22 26.56 2016 210.07 40.74 210.07 8.51 A5-A9 B5-B10 C5-C10 D5-D10 E5-E10 LITERATURE CITED

AQUATIC WEED CONTROL. 2015. Lake Wawasee and Syracuse Lake aquatic vegetation management plan – 2014 update. The Wawasee Area Conservancy Foundation. Syracuse, IN.

BHARATHAN, S. 1983. Developmental morphology of Nitellopsis obtusa. Proceedings of the Indian Academy of Sciences. Plant Sciences 92(5): 373-379.

BRAHATHAN, S. 1987. Bulbils of some chlorophytes. Proceedings of the Indian Academy of Sciences. Plant Sciences 97(3): 257-264.

BROWN, S. 2014. Starry Stonewort: Is your Lake Capable of Hosting the “Connoisseur of Clean Waters.” In: Michigan Inland Lakes Conference. Boyne Falls, MI, pp.1-25.

EDGELL. R. 2011. DNR to treat four northeastern lakes for invasive plants this summer. Indiana Department of Natural Resources, IN. http://www.in.gov/active calendar_dnr/EventListaspx? fromdate=1/1/2007&todate= 9/30/2015& display= month&type=public=seventidh=4181&view=EventDetails&information_id8361. Created on 04/25/2011. Accessed on 09/03/2015.

LITERATURE CITED FLOW. 2015. New aquatic invasive species in Lake Memphremagog. Vermont Department of Environmental Conservation, Watershed Management Division, Montpellier, VT.

GEIS, J. W., G. J. SCHUMACHER, D. J. RAYNAL, & D. P. HYDUKE. 1981. Distribution of Nitellopsis obtusa (Charophyceae: Characeae) in the St. Lawrence River: a new record for North America. Phycologia 20: 211-214.

GRAHAM, Linda. E. & Lee W. Wilcox. 1999. Algae. Prentice Hall, Inc. 700 p.

HACKETT, R. A., CARON, J. J., & A. K. MONFILS. 2014. Status and strategy for Starry Stonewort (Nitellopsis obtusa (D. A. Desvaux) J. Groves) Management. Michigan Dept. Of Environmental Quality, Lansing, Michigan.

HARGEBY, A. 1990. Macrophyte associated invertebrates & the effect of habitat permanence. Oikas 57(3):338-346. iMAPINVASIVES. 2015. IMAPINVASIVES New York. IMAPINVASIVES. www.nymapinvasives.org. Created on 07/08/3025. Accessed on 07/08/2015

LEWIS, L. A. & R. M. McCOUNT. 2004. Green Algae and the Origin of Land Plants. American Journal of Botany 91(10): 1535-1556.

LITERATURE CITED

MILLS, E. L., J. H. LEACH, J. T. CARLTON, & C. L. SECOR. 1993. Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions. Journal of Great Lakes Research 19 (1): 1-54.

MINNESOTA DEPARTMENT OF NATURAL RESOURCES (MN DNR). 2015. Invasive species starry stonewort confirmed in Stearns, Meeker county lakes. Minnesota Department of Natural Resources, St, Paul, MN.

PEARSON, J. 2015. DNR limiting weed control at Lake Tippecanoe. Indiana Department of Natural Resources. Indianapolis. IN

PULLMAN, G. DOUGLAS, & GARY CRAWFORD. 2010. A Decade of Starry Stonewort in Michigan. Summer 2010 Lakeline Report. p. 36-42.

SCHOESSER, D. 1986. Distribution and habitat of Nitellopsis obtusa (Characeae) in the Laurentian Great Lakes. Hydrobiologia 133:1-7.

SOULIE-MARSCHE, I. M. BENAMMI, & P. GEMAYEL. 2002. Biogeopraphy of living and fossil Nitellopsis (Charophyta) in relationship to new finds from Morocca. J. of Biogeography 29 (12): 1703-1711.

LITERATURE CITED

WISCONSIN DEPARTMENT OF NATURAL RESOURCES (WI DNR). 2014. Local effort to manage recently discovered invasive algae in southeast Wisconsin. Wisconsin Department of Natural Resources. Madison, WI.

WISCONSIN DEPARTMENT OF NATURAL RESOURCES (WI DNR). 2015. Aquatic invasive species by waterbody. Wisconsin Department of Natural Resources. Madison, WI.