Vulpia octoflora (Six-weeks Fescue)
Also known as: | Eight-week Fescue, Pull-out Grass, Eight-flower Six-weeks Grass |
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Genus: | Vulpia |
Family: | Poaceae (Grass) |
Life cycle: | annual |
Origin: | native |
Habitat: | sun; dry sandy or rocky soil; prairies, savannas, dunes, rock outcrops, bluffs, roadsides, open woods |
Fruiting season: | June - August |
Plant height: | 2 to 24 inches |
Wetland Indicator Status: | GP: FACU MW: FACU NCNE: FACU |
MN county distribution (click map to enlarge): | |
National distribution (click map to enlarge): |
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Detailed Information
Flower:
Spike-like panicle at the top of the stem, up to 4(8) inches long, the branches erect to slightly spreading, with 1 to 3 branches per node and spikelets (flower clusters) loosely to strongly overlapping. Spikelets are short-stalked, light green at flowering time, 4 to 10 mm (to 3/8 inch) long, flattened, lance-elliptic in outline and have 5 to 17 florets; the floret at the tip may be sterile.
At the base of a spikelet is a pair of bracts (glumes), both keeled, awnless, hairless to somewhat hairy, shorter than the spikelet, pointed at the tip, the upper glume 2.7 to 6.7 mm long and 3-veined, the lower glume 1-veined and 50-75% as long as the upper glume. Florets are surrounded by a pair of bracts (lemma and palea), the lemma hairless to somewhat hairy, obscurely veined, the lowest 2.7 to 6.5 mm long excluding a straight, .3 to 6(9)-mm awn; the palea is about as long as the lemma, 2-veined. Sterile florets are like the fertile but underdeveloped. The florets can become slightly spreading, the stalk between florets (rachilla) becoming visible.
Leaves and stems:
Leaves are alternate, ½ to 4 inches long, .5 to 1 mm wide, rolled in along the edges (involute), hairless to variously hairy. Sheaths are hairless. The ligule (membrane where the leaf joins the sheath) is .5 to 1 mm long, straight or jagged across the top edge and not fringed with hairs. Nodes are smooth. Stems are hairless, erect or sometimes spreading from the base and rising at a lower node (geniculate) or near the tip (decumbent), usually single from the base, sometimes multiple forming loose clumps.
Fruit:
Spikelets are light brown at maturity, the florets shedding individually as each grain matures, leaving the glumes behind on the stalk. Grains (seeds) are 1.7 to 3.3 mm long, dark brown.
Notes:
Six-weeks Fescue is a native, cool-season, annual grass occasionally found in dry sand or gravel prairies, rock outcrops, grassy slopes, and the occasional roadside, railroad right-of-way or Jack Pine stand, usually in full sun. It is rather variable in size, the flowering stems sometimes less than 4 inches (10 cm) tall, others up to 2 feet, and spikelets strongly overlapping to barely so. It may form loose clumps, small, dense patches, or looser colonies. With all that in mind, it can be distinguished by the short, very narrow (~1 mm wide) leaves that are rolled along the edges; panicle branches mostly erect; short-stalked spikelets to 10 mm long with 5 to 17 florets; glumes not awned, the lower glume at least half as long as the upper glume; lemmas awned, the awn straight and .3 to 6(9) mm long;
There are at least 3 vars described in different references, though the taxonomy and descriptions of these vars are not consistent across references and we won't hazard a guess which is correct; differences are the sizes of spikelets, lemmas and awns, and hairiness of the lemmas. In Minnesota, var. glauca and var. octoflora have both been recorded but the latter only once, in 1915 from southern Anoka County. Vulpia octoflora resembles some other Fescues (Festuca spp.), and was once included in that genus (F. octoflora); common traits are very narrow, involute leaves, a more or less spike-like panicle, multi-flowered spikelets, lemmas awned and glumes not. Vulpia is noted as being annual with having a single stamen in a floret, where Festuca is perennial with 3 stamens, and the Minnesota Festuca species are all much more densely clump-forming.
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More photos
- Vulpia octoflora plants
- Vulpia octoflora plants ©Matt Lavin
- zig-zag rachis and overlapping spikelets
Photos by Peter M. Dziuk taken in Renville County. Vulpia octoflora plant by Matt Lavin, via Wikimedia Commons, used under CC BY-SA 2.0
Comments
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