Poa sphondylodes var. sphondylodes :
China (Asia)
Japan (Asia)
North Korea (Asia)
South Korea (Asia)
Russian Federation (Asia)

Poa palustris L.:
Argentina (South America)
Canada (North America)
Chile (South America)
Italy (Europe)
Japan (Asia)
Ireland (Europe)
Kriti (Europe)
Hungary (Europe)
Kazakhstan (Asia)
Mongolia (Asia)
Greenland (North America)
Netherlands (Europe)
Norway (Europe)
Sweden (Europe)
New Zealand (Oceania)
Pakistan (Asia)
Greece (Europe)
Poland (Europe)
Russian Federation (Asia)
Romania (Europe)
South Korea (Asia)
Switzerland (Europe)
Tajikistan (Asia)
Turkmenistan (Asia)
Bulgaria (Europe)
Ukraine (Europe)
United Kingdom (Europe)
United States (North America)
France (Europe)
Finland (Europe)
Germany (Europe)
Denmark (Europe)
Czechoslovakia (Europe)
Yugoslavia (Europe)
North Korea (Asia)
Kyrgyzstan (Asia)
China (Asia)
India (Asia)
Belgium (Europe)
Austria (Europe)

Poa grandispica Keng ex L. Liou:
China (Asia)

Poa sphondylodes var. koidzumii Honda:
Japan (Asia)

Poa sphondylodes var. subtrivialis Ohwi:
Japan (Asia)
China (Asia)

Poa sphondylodes var. kelungensis (Ohwi) Ohwi:
Taiwan (Asia)

Poa kelungensis Ohwi:
Taiwan (Asia)

Poa sphondylodes subsp. kelungensis (Ohwi) T. Koyama:
Taiwan (Asia)
China (Asia)

Poa adspersa Drejer:
Sweden (Europe)

Poa crocata Michx.:
Canada (North America)

Poa strictula Steud.:
China (Asia)
Japan (Asia)
North Korea (Asia)
Russian Federation (Asia)
South Korea (Asia)

Poa serotina Ehrh.:
Kazakhstan (Asia)
Uzbekistan (Asia)

Poa janczewskii Zapal.:
Ukraine (Europe)

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Distribution: Kashmir; widely distributed in temperate regions of the northern hemisphere.

Swamp Meadow-grass is distinguished from Poa nemoralis by its longer ligules, from Poa trivialis by its smooth leaf-sheaths and blunt ligules, and from Poa pratensis by its longer ligules and the absence of rhizomes.

Poa palustris, like P. nemoralis, is one of the most complicated and polymorphic species. Hybridization with P. nemoralis, coupled with apomixis, has formed a series of morphologically and genetically distinct populations treated here as P. lapponica.

Despite its great polymorphism, Poa palustris has not been divided satisfactorily into stable taxa. Its distribution in China seems to be quite restricted, limited to the northern regions only. It is probably naturalized in central and southern areas. In the mountains of the south and southwest it is replaced by the allied species P. faberi. In E China, Japan, and Korea it is very close to, and probably replaced by, a third, related species, P. sphondylodes. Unusual plants in Anhui differ by the glumes and lemma being much narrower with a prominent vein. Some populations of P. palustris in N China and even in the Russian Far East differ from normal P. palustris by the appearance of characters of P. sphondylodes: ligule longer than 3–4 mm, upper node infrequently only to 1/3 way up culm, leaf blades soft and flat, panicle branches sometimes very short, spikelets crowded at very base of branches, and longest branches at 2nd node of panicle. Both Ohwi (Fl. Jap. 164. 1965) and Koyama (Grasses Japan Neighboring Regions, 96. 1987) reported P. palustris with a ligule to 5 mm from Japan; similarly Chung (Korean Grass. 71. 1965) and Lee (Man. Korean Grass. 154. 1966) from Korea. Poa palustris with such long ligules occurs in the Pacific area only, and these plants might be closer to P. sphondylodes. Such plants may also be found in coastal areas of China.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stems compressed, flattened, or sulcate, 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 conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf she ath or blade keeled, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, 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 an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence with 2-10 branches, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelets with 3-7 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 glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes distinctly unequal, Glumes shorter than adjacent lemma, Glumes keeled or winged, Glumes 3 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Lemma with long cobwebby white hairs, Palea present, well developed, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Loosely tufted short-lived perennial; culms (15-)40-80(-150)cm high, erect or spreading, sometimes geniculate at the base. Leaf-blades flat, 5-20cm long, 1-2(-4)mm wide, flaccid, gradually tapering to a stout point, scaberulous on the margins and both surfaces; ligule rounded, 1-3mm long. Panicle narrowly pyramidal 10-20(-30)cm long, spreading; branches mostly in distant clusters of 3-6, scabrid. Spikelets 2-5-flowered, ovate to oblong, 3-5mm long, yellowish-green or purplish; glumes lanceolate to narrowly ovate, the lower 2-3 mm long, 1-3-nerved, the upper broader, 2.5-3 mm long, 3-nerved; lemmas narrowly oblong in side-view, 2.5-3 mm long, obtuse, ciliate on the keel and marginal nerves, with sparse wool at the base; palea almost as long as the lemma, scabrid along the keels; anthers 1.3-1.5 long.

Culms loosely tufted, 40–80(–120) cm tall, erect or slightly geniculate, rarely branching near base; nodes 5 or 6, uppermost at or above middle of culm. Shoots extravaginal. Leaf sheath smooth or rarely scabrid; equal to or shorter than blade; blade flat, 8–20 cm × 2–3(–5) mm; ligule 2–3 mm. Panicle slightly contracted, 10–20(–30) cm; branches obliquely ascending, 3–8 per node, basal primary branch 1/2–2/3 as long as panicle with spikelets in distal 1/2. Spikelets ovate-oblong, yellowish green, 2.5–5(–7) mm, florets (2–)3–5(–7); rachilla scabrid or warty, rarely smooth; glumes almost equal, 2–3.5(–4) mm; lemma 3–3.5(–4) mm, keel shortly villous for 1/2 of length, marginal veins for 1/3, apex golden or rarely silvery, membranous; callus webbed; palea keel scabrid, area between keels smooth and glabrous. Anthers 1.2–1.5(–2) mm. Fl. Jun–Jul. 2n = 28, 30, 32, 42.

Isotype for Poa rotundata Trin.
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): -. Mertens
Locality: Aleutian Islands, Alaska, United States, North America

Meadows among scattered thickets on slopes, marshy grasslands; 300–3500 m. Anhui, Hebei, Heilongjiang, Henan, Nei Mongol, Xinjiang [India, Japan, Kazakhstan, Korea, Kyrgyzstan, Mongolia, Pakistan, Russia, Tajikistan; SW Asia, Europe, North America].

Foodplant / parasite
Blumeria graminis parasitises live Poa palustris

Collection Sites: world map showing specimen collection locations for Poa palustris

Barcode of Life Data Systems (BOLD) Stats
                                                             

Specimen Records:	16
Specimens with Sequences:	57
Specimens with Barcodes:	28
Public Records:	25
Species:	1
Species With Barcodes:	1

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 15
Species: 27
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Comments: Somewhat threatened by land-use conversion, habitat fragmentation, and forest management practices (Southern Appalachian Species Viability Project 2002).