North American Seaside Arrowgrass Gardens: Toxins and Water Quality

Summary: North American seaside arrowgrass gardens defend wetland populations and water quality but deal ingestors of marsh and seaside arrowgrasses toxic brews.

seaside arrowgrass (Triglochin maritimum): Steve Dewey, Utah State University, Bugwood.org, CC BY 3.0 United States, via Forestry Images

The phrase drop dead gorgeous assumes a poignant prescience when applied to North American seaside arrowgrass gardens whose native herbs accumulate toxins that act massively and mercilessly upon foraging livestock and people.

The toxic substances taxiphillin and triglochinin blast hydrogen cyanide into livestock grazing, and people foraging for, fresh shoots in early spring and bring on respiratory failure. Just 0.5 percent of body weight causes death by poisoning if ingestion comes in one fell swoop since repeated under-consumption never carries the non-cumulative toxins over. No federal, provincial, state or territorial legislation deems seaside arrowgrass a weed, whose designation describes damage to crop yields, ecosystem well-being, human health and species diversity.

The flowering, fruiting, seeding herb epitomizes poisonous and weedy plants that end soil erosion and surface runoff, enforce food chains and webs and ensure ecosystem integrity.

Seedlings furnish one dark green, 0.12- to 0.24-inch- (3- to 6-millimeter-) long embryonic leaf, called a cotyledon, with a bent or hooked tip and rounded cross-section. Seaside arrowgrass seedlings, as members of the Juncaginaceae family of arrowgrass herbs, grow into grasslike plants with grasslike leaves in such alkaline, grassy wetlands as marshes. Their mature stages have 7.87- to 39.37-inch- (20- to 100-centimeter-) long stems, whose bases hold the previous season's basal growth on short rootstalks with fibrous roots. A hoodlike projection, called a ligule, indicates the meeting of the leaf's loose upper part, called a blade, and the lower stem-encasing part called a sheath.

Last year's 0.28- to 0.98-inch- (7- to 25-millimeter-) long, 0.04- to 0.08-inch- (1- to 2-millimeter-) wide sheaths jumpstart foliar growth in North American seaside arrowgrass gardens.

Four to ten basal, fleshy, grasslike, 0.87- to 5.91-inch- (2.2- to 15-centimeter-) long, 0.04- to 0.24-inch- (1- to 6-millimeter-) wide leaves keep semicircular looks in cross-section.

Green-white, 0.04- to 0.16-inch- (1- to 4-millimeter-) wide flowers line terminal, 3.94- to 19.68-inch- (10- to 50-centimeter-) long, 0.06- to 0.28-inch- (1.5- to 7-millimeter-) wide racemes. Every flower mingles one pistil, three green 0.05- to 0.07-inch- (1.3- to 1.7-millimeter-) long sepals, three green same-sized petals, six stamens and six feathery wind-pollinated stigmas. Fruit production nudges three to six oblong, single-seeded, 0.19- to 0.28-inch- (5- to 7-millimeter-) long capsules per flower for a seed production of 600 per plant.

North American seaside arrowgrass gardens offer elliptical, yellow-brown, 0.06- to 0.14-inch- (1.5- to 3.5-millimeter-) long, 0.03- to 0.04-inch- (0.7- to 1-millimeter-) wide seeds of unknown viability.

Soil temperatures of 68 to 86 degrees Fahrenheit (20 to 30 degrees Celsius) provoke germination in seaside arrowgrass, also called saltmarsh arrowgrass, shore arrowgrass and spikegrass.

Defensive contributions to water quality and to wetland integrity and precise identification of soil viability qualify as two timely research concerns regarding dangerous, mysterious seaside arrowgrass. Like all arrowgrasses, seaside arrowgrass, described by Råshult-born Swedish botanist Carl Linnaeus (May 23, 1707-Jan. 10, 1778) and scientifically called Triglochin maritimum (three-pointed sea-plant), remains treacherous. Marsh arrowgrass, a fellow Juncaginaceae family member and native North American perennial, likewise shares toxic substances and wetland occurrences and similarly suffers no unwelcome weed designations.

May- to August-blooming North American seaside arrowgrass gardens trouble wetland gardeners and naturalists least when signs tell of toxins too toxic to take in one gulp.

closeup of seaside arrowgrass flowers: Rob Routledge, Sault College, Bugwood. org, CC BY 3.0 United States, via Forestry Images

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

seaside arrowgrass (Triglochin maritimum): Steve Dewey, Utah State University, Bugwood.org, CC BY 3.0 United States, via Forestry Images @ http://www.forestryimages.org/browse/detail.cfm?imgnum=1459011

closeup of seaside arrowgrass flowers: Rob Routledge, Sault College, Bugwood. org, CC BY 3.0 United States, via Forestry Images @ http://www.forestryimages.org/browse/detail.cfm?imgnum=5497009

For further information:

Dickinson, Richard; and Royer, France. 2014. Weeds of North America. Chicago IL; London, England: The University of Chicago Press.

Linnaeus, Carl. 1753. "2. Triglochin maritimum." Species Plantarum, vol. I: 339. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/358358

"Triglochin maritimum L." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/17000015

Weakley, Alan S.; Ludwig, J. Christopher; and Townsend, John. 2012. Flora of Virginia. Edited by Bland Crowder. Fort Worth TX: BRIT Press, Botanical Research Institute of Texas.