Leymus mollis

Leymus mollis
ssp. mollis in California
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
(unranked):	Commelinids
Order:	Poales
Family:	Poaceae
Genus:	Leymus
Species:	L. mollis
Binomial name
Leymus mollis (Trin.) Pilg.
Synonyms
Elymus mollis

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Leymus mollis (syn. Elymus mollis) is a species of grass known by the common names American dune grass, American dune wild-rye, sea lyme-grass, strand-wheat,^[1] and strand grass.^[2] Its Japanese name is hamaninniku.^[3] It is native to Asia, where it occurs in Japan, China, Korea, and Russia, and northern parts of North America, where it occurs across Canada and the northern United States, as well as Greenland.^[1][2] It can also be found in Iceland.^[1]

This is a rhizomatous perennial grass with erect stems growing up to 1.7 meters tall. The leaf blades can be nearly a meter long in ssp. mollis, and up to 1.5 centimeters wide. The flower spike is up to 34 centimeters long by 2 wide. Each spikelet may be up to 3.4 centimeters long and contain up to six florets. There are two subspecies. Subspecies villosissimus is mostly limited to arctic regions, and is mainly coastal. It is usually a smaller plant than ssp. mollis.^[4] The two subspecies are otherwise hard to tell apart, even when growing sympatrically. The most reliable character to use to distinguish them is the type of hairs on the glumes and lemmas;^[5] ssp. villosissimus has long, soft, sometimes shaggy hairs (villous), while ssp. mollis has fine, thin hairs (pilose), and generally fewer of them.^[4] There is no awn.^[1]

This grass usually grows in coastal habitat, especially on dunes. It can be an important part of dune ecology. The grass usually grows on the foredune and on embryo dunes, less often on the backdune.^[6][7][8] It is one of the very first plants to establish in the process of ecological succession in the early stages of the development of a sand dune.^[8] In these loose dunes facing the ocean the plants tolerate salt spray, salty sand, little to no fresh water, unstable substrates, occasional inundation during storms, low nutrient levels, and abrasion by wind, water, and ice storms. Seedlings may become buried. This type of environment causes stress in a plant. The grass grows from a large rhizome that anchors it into shifting and unstable sands. When there are many plants on a dune, their rhizomes form a network that helps to stabilize it, preventing erosion. The network becomes "the skeleton of the foredune."^[6] This makes the grass a valuable species for landscape rehabilitation in native beach habitat.^[7]

This grass hybridizes with a number of other species, including Psathyrostachys juncea, Leymus innovatus, Leymus salinus, and Leymus arenarius.^[9] Hybrids with the latter species are not uncommon in southern Greenland.^[10]

Other plants that occur with the grass include Lathyrus japonicus, Achillea millefolium, Festuca rubra,^[8] Ammophila breviligulata, Rhus typhina, Rosa rugosa,^[1] Arctanthemum arcticum.^[5] It also grows with mosses such as Pleurozium shreberi and Polytrichum spp. and lichens such as Cladina spp.^[8] It was observed to be one of the most common plants in the arctic nesting sites of the Snow Goose. It is thought that the geese prefer the overall ecosystem that hosts the grass, rather than favoring the grass itself.^[5]

The grass has been studied for possible use in the science of wheat breeding. The two plants can be easily bred. The dune grass is stress-tolerant with its adaptation to harsh environments; breeders hope that some of these traits for stress tolerance can be transferred to wheat. Drought tolerance is of particular interest.^[11][12]

This grass has had a number of other human uses. The Makah, Nitinaht, and Quileute used bunches of the thick roots to rub the body during bathing. Yupik peoples use the leaves to make mats, baskets, bags, and ropes for hanging fish to dry. The Hesquiat weave the leaves into handles for sacks. The Kwakwaka'wakw make baskets and hats from the leaves and traditionally have used them to line the boxes in which they cooked lupine roots. The Nitinaht used the pointed leaves to sew and tie. The Haisla and Hanaksiala used the grass to line pits in which they prepared the oil of the eulachon fish. The Quinault placed salal fruits on a bed of the leaves to dry.^[13] Inuit in Canada have traditionally used Leymus mollis to treat stomach problems and to weave baskets. They used dried leaves to insulate their boots.^[14]

While it is not a rare or threatened plant, its populations can be affected by processes that degrade and destroy its coastal habitat. Concerns include development, storm damage, and the impact of recreational activities.^[1] In some areas it has been displaced by introduced species of plants, such as Ammophila arenaria.^[3]

Cultivars available include 'Reeve' and 'Benson'. The latter was named for Benny Benson, the thirteen-year-old boy who designed the official flag of Alaska. It was bred for use in the revegetation of eroded dunes.^[15]

See also

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References