Elymus semicostatus (Steud.) Melderis

A very variable species ranging from small slender plants to tall robust ones; the leaves are usually flat, but are sometimes convolute; the spike is often rather lax but may be very dense (var. validum); pubescence is mostly short and sparse, but in some plants (var. thomsonii) the sheaths and blades are densely villous.

In his Annotated Catalogue, Stewart cites sheet 25056a from Swat under Agropyron thomsonii Hook.f., whereas it is in fact Agropyron semicostatum var. thomsonii, a quite different plant. Agropyron thomsonii has a curved awn and silky-villous lemmas; it does not occur in Pakistan.

1000-4000 m.

Tufted perennial, apparently, without rhizomes; culms 45-135 cm high, erect or geniculately ascending, slender or stout. Leaf-blades Pat, sometimes convolute, 15-30 cm long, 4-8(-12) mm wide, smooth or scabrid above, smooth beneath, sometimes the sheaths and blades villous. Spike 8-30 cm long erect, nodding or curved; rhachis joints scabrid along the margins. Spikelets 6-8-flowered, 20-30 mm long (excluding the awns); glumes unequal, elliptic-lanceolate, with prominent scabrid nerves, acute or acuminate, the lower 10-16.5 mm long, the upper 11-18 mm long; lemma elliptic, 12-14 mm long (excluding the awn), scabrid or puberulous on the back, produced at the tip into an awn (4-) 12-18 mm long; palea about three-quarters the length of the body of the lemma; anthers 3-4 mm long.

Afghanistan, Himalaya (Kashmir to Sikkim).

Distribution: Pakistan (Punjab, N.W.F.P., Gilgit & Kashmir); Afghanistan and the Himalayas eastwards to Sikkim.

1700-4000 m

Fl. & Fr. Per.: July-August.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blade auriculate, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades more or less hairy, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence simple spikes, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence single raceme, fascicle or spike, Inflorescence spikelets arranged in a terminal bilateral spike, Rachis dilated, flat, central axis to which spikelets are attached, Flowers bisexual, Spikelets p edicellate, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 3-7 florets, Spikelets with 8-40 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel hairy, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes shorter than adjacent lemma, Glumes equal to or longer than adjacent lemma, Glumes 4-7 nerved, Lemma similar in texture to glumes, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn 1-2 cm long, Lemma awned from tip, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lem ma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear, Caryopsis hairy at apex.

Elymus semicostatus là một loài thực vật có hoa trong họ Hòa thảo. Loài này được (Nees ex Steud.) Melderis mô tả khoa học đầu tiên năm 1978.