Poa chaixii (Broad-leaf Bluegrass)
|Also known as:||Broad-leaved Meadow Grass|
|Habitat:||part shade, shade, sun; disturbed soil; woods, meadows, trail edges|
|Fruiting season:||July - August|
|Plant height:||2 to 4 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Open panicle 4 to 8 inches long, oval-elliptic to pyramidal in outline, usually erect, sometimes slightly nodding, the branches ascending to spreading. Spikelets (flower clusters) are short-stalked, light green, flattened, lance-elliptic in outline, 4 to 9 mm (to ~1/3 inch) long with 2 to 6 florets; the uppermost floret may be sterile.
At the base of a spikelet is a pair of bracts (glumes) that are both pointed at the tip, awnless, hairless, keeled, rough along the keel, the lower glume 2.5 to 3 mm long and 1 to 3-veined, the upper glume 3 to 4 mm long and 3-veined. Surrounding a floret is a pair of bracts (lemma and palea), the lemma 3.5 to 4.5 mm long, hairless, pointed at the tip, keeled, 5-veined, rough along the veins and edges; the palea is as long as the lemma, 2-veined, rough along the veins. The thickened base of the floret (callus) and the stalk between florets (rachilla) are both hairless.
Leaves and stems:
Leaves are mostly basal with 2 or 3 alternate leaves widely spaced along the stem. Leaves are flat or folded, 5 to 15 mm (to ~½ inch) wide, hairless, boat-shaped at the tip. Basal leaves are lax and up to 18 inches long, stem leaves are erect to ascending, stiffer, and much shorter. Old, dead basal leaves persist to the next season.
The sheath is hairless, compressed, has a winged keel along the back, and the edges are fused for at least half their length (closed sheath). The ligule (membrane where the leaf blade joins the sheath) is .5 to 1.5 mm long and lacks a fringe of hairs. Nodes are smooth. Stems are unbranched, mostly erect, slightly compressed, multiple from the base forming clumps, and lack rhizomes or stolons.
Broad-leaf Bluegrass is a cool-season grass introduced from Europe. To-date it has only been recorded on Hunter's Hill in Duluth, the first time in 1937 and periodically since then, most recently in 1983; 35 years later we found it still there. It may be persistent but does not appear to be terribly aggressive. In its native range it is found in alpine meadows, floodplains and moist forests.
Poa species are recognized by their (usually) closed sheaths, leaves with boat-shaped tips, and often long, cobwebby hairs around the base of the floret (callus). Broad-leaf Bluegrass is distinguished by its clump-forming growth, the basal clump a mix of new and old leaves; leaves 5 to 15 mm (to ~½ inch) wide, flat or often folded, the upper stem leaves erect and rather short and the basal leaves much longer and more lax; ligule about 1 mm long; sheaths closed for half or more of their length, compressed with a winged keel on the back; spikelets in an open panicle, 2 to 6 florets per spikelet; florets rough along the veins and edges, 3.5 to 4.5 mm long, palea as long as the lemma. The callus is hairless, unlike many of its relatives.
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Where to buy native seed and plants ↓
- Broad-leaf Bluegrass plant
- Broad-leaf Bluegrass plant
- Broad-leaf Bluegrass plants in early June
- scan of plant
- basal leaf clumps with persistent old, dead leaves
- folded uppermost stem leaf
- flowering panicle
- branch of mature panicle
Photos by K. Chayka and Peter M. Dziuk taken in St Louis County.
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