Patis racemosa (Black-fruited Rice Grass)

Plant Info
Also known as: Black-seeded Mountain Rice Grass
Genus:Patis
Family:Poaceae (Grass)
Life cycle:perennial
Origin:native
Habitat:part shade, shade; average to moist soil; rich woods, deciduous forest, Jack pine stands
Fruiting season:July - September
Plant height:12 to 36 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: indistinct Cluster type: panicle

[photo of panicle] Loose, erect to nodding, branching cluster at the top of the stem, up to 10 inches long, with 1 or 2 branches per node. Branches are 1 to 4 inches long, initially appressed becoming ascending to widely spreading, with 2 to 5 spikelets (flower clusters) per branch. Spikelets are loosely overlapping at the tip of a branch, short-stalked, narrowly lance-elliptic in outline and have a single floret.

[photo of panicle branch] At the base of a spikelet is a pair of bracts (glumes), both about equal in size and shape, hairless, awnless, obscurely 5 to 7-veined (more prominent when dry), oblong-elliptic with a pointed tip, 6 to 8 mm (to 1/3 inch) long and as long as the spikelet. Florets are surrounded by a pair of bracts (lemma and palea), both leathery, variously hairy and turning blackish with maturity, the lemma narrowly elliptic, the body 4.5 to 8 mm long tapering to a slightly twisted awn 10 to 25 mm (3/8 to ~1 inch) long; the palea is about as long as the lemma and 2-veined.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are 4 to 10 inches long, 8 to 16 mm (1/3 to 2/3 inch) wide, lance-linear, flat, thin and arching, with surfaces sparsely hairy to rough-textured. The lowest leaves are reduced to sheaths with a blade less than 1 inch long.

[photo of sheath, node and stem] The sheath is smooth to rough-textured, sometimes minutely hairy at the tip near the edges. The ligule (membrane where the leaf joins the sheath) is a fringe of hairs .5 mm long or less. Nodes are densely short-hairy. Stems are unbranched, erect to ascending, hairless except minutely hairy near the nodes, multiple from the base and forming loose clumps from short, knotty rhizomes.

Fruit: Fruit type: seed without plume

[close-up of spikelets] Spikelets are dull green to light brown at maturity, the blackish florets shedding individually as each grain matures, leaving the glumes behind on the stalk. Grains (seeds) are 5 to 6 mm long with an abrupt taper to a beak at the tip.

Notes:

Black-fruited Rice Grass, also known by synonyms Piptatherum racemosum and Oryzopsis racemosa, is a common woodland species found in more than half of Minnesota. It is distinguished from all other grasses by the single-flowered spikelets, hairless glumes as long as the spikelet, blackish lemmas with long awns, bladeless lower sheaths, and ligules of a very short fringe of hairs. The overall form is similar to Brachyelytrum species, which have tiny glumes, more distinctly veined lemmas, shorter and stiffer leaves with distinct cross partitions on the lateral, parallel veins.

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More photos

Photos courtesy Peter M. Dziuk taken in Pine, Renville and Winona counties. Photo of blackish lemma ?Fontenelle Nature Association, used by permission.

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