Poaceae of the Canadian Arctic Archipelago

S.G. Aiken, L.L. Consaul, and M.J. Dallwitz

Leymus mollis (Trin.) Hara

Sea lyme-grass.

Bot. Mag. (Tokyo) 52: 232. 1938.

Elymus mollis Trin. In Spreng. Neue Entdeck ii.72. Elymus arenarius L. subsp. mollis (Trin.) Hultén. Leymus mollis (Trin.) Hara. invalidly published. Löve, A. Feddes Repertorium 95: 425–521. 1985.

Type: lectotype from Aleutian Islands, possible isotype LE.

Elymus arenarius var. villosissimus (Scribn.) Polunin, Bull Natl. Mus. Canada 92 (Biol. Ser. 24): 96. 1940.

Plants not caespitose; less than 15 cm high, or more than 15 cm high; 15–55 cm high (to 100 cm, but rarely as tall north of 60°N in the Canadian Arctic Archipelago). Ground-level or under-ground stems horizontal, or vertical and often branched (acting as a sand binder); rhizomatous (growing as an active sand binder); elongate, or compact; 1–3 mm wide. Scales present; smooth (but veins prominent); 20–35 mm long; glabrous. Aerial stems erect; densely hairy. Leaves distributed along the stems (sometimes appearing basal in a moving sand habitat). Sheaths with the margins fused only in the lower part; glabrous. Ligules 0.5–1 mm long; a fringed membrane; hairy; transversely oblong; apices truncate; erose. Blades 65–170 mm long; 2–9 mm wide; spreading; rolled in bud; with blade auricles (an extension of the collar); flat (usually), or folded (rolling on drying); midvein similar in size to other veins in the leaf. Blades adaxial surface scabrous. Blades abaxial surface glabrous (sometimes glaucous).

Flowering culm nodes rooting at the lower nodes; not exposed (internodes hairy). Flag leaf sheaths inflated. Inflorescence spicate; dense; linear; 5–9.5 cm long (in the arctic islands, elsewhere to 15 cm long); 10–20 mm wide. Inflorescence. Inflorescence main axis hairy. Spikelets. Spikelets sessile (with one apical spikelet and at every node several, usually 3, spikelets); disarticulating above the glumes; laterally compressed; lanceolate; 10–21 mm long; 2–3.5 mm wide. Florets per spikelet (1–)2–3(–4). Glumes. First glume 0.85–1 × the length of the second glume; 0.9–1 × spikelet length (as long as spikelet); 9.5–17 mm long; linear; with trichomes (hairy); margins glabrous; veins 1–3; apex acuminate. Second glume as long, or longer than the spikelet; almost as long as, or longer than, the lowest floret; linear; 10–19 mm long; densely pubescent; veins 1–3(–5). Rachilla internode 2–4 mm long; hairy. Rachilla pronounced between the florets; extending beyond the uppermost floret. Lemmas. Lemma 8.6–18.5 mm long; lanceolate; rounded on the back; surface dull; surface hairy; veins (4–)7. Lemma apex acuminate (attenuate); entire; ciliate (densely pubescent); awnless. Palea well developed; 8.8–14 mm long; with hairy veins. Perianth reduced to lodicules. Anthers 4.5–7 mm long. Styles 2. Fruit sessile. Fruit dry; indehiscent. Fruit 7–10 mm long. Seeds 1.

Chromosome information. 2n = 28 (Tzvelev (1976) c.f. L. arenarius L. 2n=56).

Distribution. Amphi-Atlantic (Iceland, Greenland, North America, and eastern Asia). Low arctic. Range in the Canadian Arctic Archipelago limited. Arctic Islands: Baffin, Victoria.

Ecology and habitat. Substrates: around the margins of ponds; halophytic; sand. Habitats: Littoral, growing on dunes and sandy places near seashore, or lake shores. Common on sandy beaches of Frobisher Bay, e.g. near the Hudson Bay Store, Apex, and at Peter Head.

Taxon as an environmental indicator. When this sand binder species, that naturally grows near the high tide line, is found inland, it is usually indicative that gravel from a nearby beach has been moved and used as land fill. The species becomes weaker away from the influence of moving sand and when transplanted inland, dies out after a few seasons.

Notes. This species is a member of the grass tribe TriticeAe, where there has been much discussion about generic AlignmenTs, see for example the synonymy for Elymus alaskanus.

The separation of L. mollis and L. arenarius at species level is probably well justified on a combination of morphological and ploidal differences, even if the morphological differences are few and all the hairiness characters may be genetically interconnected.

The taxon in the Canadian Arctic Archipelago is subsp. mollis. On continental North America L. mollis subsp. villosissimus A. Löve & D. Löve has been recognised. Bot. Not. 128: 503. 1976. Problems with this taxon are noted in the PAF Checklist.

Illustrations. • Habitat photograph. Tall grass plants growing as a and binder binder in disturbed gravel, Manitoba, Churchill, tidal estuary of the Churchill River. Aiken and Brysting, 01–028. CAN. • Habitat photograph. Growing as a sand binder in disturbed gravel, Nunavut, Kingaok (Bathurst Inlet). Photograph by A. Robinson. • Close-up of plants. Plants more than 70 cm tall, growing in gravel at the base of a satellite tower, an indication that the gravel had been brought from closer to the seashore. Manitoba, Churchill, Beech Bay near airport. Aiken and Brysting, 01–028. CAN. • Close-up of inflorescence. Compact spicate inflorescence, approximately 12 cm long. at anthesis. Manitoba, Churchill, Beech Bay, near airport. Aiken and Brysting, 01–028. CAN. • Close-up of spikelets. Portion of the compact spicate inflorescence at anthesis: left, young yellow anther just protruding from the lemma left: right, spent anthers, right. Note hairs on the margins of the lemmas. Aiken and Brysting, 01–028. CAN. • Close-up of spikelet at anthesis. Spicate inflorescence at anthesis with anthers dangling on long filaments. Canada. Quebec, Poste-de-la- Baleine, 15 July, 1982, J. Cayouette. (DAO). • Distribution map.