Bog Bluegrass

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, Stem internodes hollow, Stems with inflorescence less than 1 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 sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, 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, wit h 1 spike, fascicle, glomerule, head, or cluster per stem or culm, 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 straig ht, 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.

Poa paludigena is a species of grass known by the common names bog bluegrass, marsh bluegrass, slender marsh bluegrass, and Patterson's bluegrass. It is native to the northeastern United States.

This perennial grass forms loose tufts of slender, weak, pale green stems up to 55 centimeters tall. It has no stolons and rarely has small rhizomes. The thin leaves are no more than 2 millimeters wide and 10 centimeters long. The inflorescence is an open panicle of just a few small spikelets. It is difficult to distinguish from related species without microscopic examination. It is similar to other Poa such as Poa compressa.

This grass grows in cool wetland habitat types such as bogs, swamps, and wet meadows. It may grow in mucky spots with Sphagnum moss and spring-fed swamp habitat dominated by Fraxinus nigra and Betula alleghaniensis. It is not an aquatic plant, but it is found in very wet environments. Other species in the habitat may include Alnus incana ssp. rugosa, Calamagrostis canadensis, Cypripedium reginae, Doellingeria umbellata, Eupatorium perfoliatum, Galium asprellum, Geum rivale, Impatiens capensis, Larix laricina, Onoclea sensibilis, Polygonum sagittatum, Rhamnus alnifolius, Symphyotrichum lanceolatum, Symphyotrichum puniceum, and Thelypteris palustris.

Potential threats to the species include destruction or degradation of the fragile wetland communities where it occurs, but none of the occurrences appear to be in imminent danger of extirpation.