Flower:

Wispy, open, branching cluster generally taller than wide when fully expanded, up to 17 inches tall and 13 inches wide (typically much reduced), with diffuse, wiry, widely-spreading branches. Branches are straight, diverging multiple times off the central stalk (rachis), green turning reddish purple with maturity, rough textured with clusters of long, straight white hairs in the branch axils, and a spikelet (flower cluster) at the tip of each branchlet. The base of the cluster is sometimes enclosed by a leaf sheath.

Spikelets are usually purplish, sometimes olive-colored, 3 to 8 mm long, 1.5 to 2 mm wide with 4 to 12 florets and a pair of bracts (glumes) at the base. Lower and upper glumes are equal in size or nearly so, 1.2 to 2.2 mm long, lance-shaped with a pointed tip and are rough-hairy along the keel. Florets are slightly flattened, each surrounded by a pair of bracts (lemma and palea) that are slightly larger than the glumes, 1.4-2.5 mm long, lance to egg-shaped with a pair of prominent lateral veins, a pointed tip, and rough along the keel; palea are also hairy around the edges.

Leaves and stems:

Leaves are mostly basal, 4 to 12 inches long, up 1/3 inch wide, both surfaces usually with sparse fine hairs but variable, one or both may be smooth. The sheath is open, forming a long “V” at the front or sometimes more closed with overlapping edges. Sheath surfaces on upper leaves are mostly smooth, the lower more densely hairy with long, spreading hairs, sometimes just hairy along the edges and/or at the tip where it joins the blade. The ligule (membrane where the leaf joins the sheath) is a band of long, white hairs about ¼ inch long. Nodes are hairless and green to purplish.

Stems are unbranched and smooth. Plants are clump forming with short rhizomes, with old leaves often persisting to the next season.

Fruit:

The entire cluster breaks off at maturity, blowing to new locations tumbleweed fashion, spikelets turning tan as lemmas fall away with the glumes persistent. Grains (seeds) are a rich golden brown, oval, .6 to .7 mm long, .5 mm wide.

Notes:

Purple Lovegrass (also called Tumble Grass) is a species of dry, open prairie and sandy roadsides. Minnesota is at the northern edge of its range; it is mostly found in counties bordering the Mississippi River as far north as southern Cass County, throughout the Anoka Sand Plain, and counties along the St. Croix River up to Pine County. It is one of three similar purple tumbleweed grasses found in Minnesota, the other two are Fall Witch Grass (Digitaria cognata) and Witchgrass (Panicum capillare), both of which have spikelets with single florets where Purple Lovegrass has 4 or more florets per spikelet. It can further distinguished from D. cognata by its mostly basal leaves, unbranched stems, and long hairs about the ligule where D. cognata has branching stems with leaves throughout the branches and membranous ligules with jagged edges. P. capillare also differs in having branching stems and is an annual, is a much larger (taller) and stout plant that is densely hairy throughout with larger cornstalk-like leaves.