Grass family (Poaceae)
Description: This perennial grass is 1-2' tall and tufted at the base with erect to widely spreading culms. Each culm has 3-4 alternate leaves; it is unbranched, light green to light tan, glabrous, and mostly hidden by the sheaths. The leaf blades are 3-8 mm. across and up to 10" long; they are medium green, ascending to widely spreading, and usually hairless (except near the base of the blade). The leaf sheaths are open, rather loose, and more or less hairy. However, sometimes the upper sheaths are hairless. Each ligule consists of a ring of long white hairs; these hairs are conspicuous at the junction of each blade and sheath.
The inflorescence is up to 15" long and 12" across, globoid-ovoid in overall shape, and larger than the rest of the plant; it consists of an airy panicle of spikelets with widely spreading branches. Along the central axis (rachis) of this panicle, there are whorls of 3 branches, which divide into smaller branches. At each whorl along the central axis, there is a small tuft of hair. Sometimes smaller tufts of hair can be found where the branches divide into smaller branches. These branches are very slender and somewhat stiff. Individual spikelets occur on slender pedicels; these pedicels are usually longer than the spikelets. The spikelets are about 4-7 mm. long, 1.5 mm. across, and flattened; they are pale purple to bright purple when the florets bloom, but later become light tan. Each spikelet consists of a pair of glumes and 5-15 lemmas in two columnar ranks. The lemmas are 1.5–2.0 mm. long, ovate, folded along their keels, and 3-veined. The glumes are lanceolate, folded along their keels, and a little shorter than the lemmas. The blooming period occurs from late summer to early fall. At maturity, the entire inflorescence can become detached and blow about in the wind, thereby distributing the seeds. The root system is fibrous and rhizomatous.
Cultivation: Preferred growing conditions are full sun and dry barren soil containing sand or gravel. Because of a C4 metabolism, most vegetative growth occurs during the summer when the weather is warm. This low-growing grass is resistant to drought.
Range & Habitat: Purple Love Grass is occasional to locally common throughout Illinois; this native grass has been found in every county (see Distribution Map). Habitats include hill prairies, sand prairies, upland savannas and sandy savannas, limestone glades, sandy or gravelly areas along railroads, sandy or gravelly roadsides, sandy paths, and fields. Disturbed sandy areas are preferred.
Faunal Associations: There is limited information about floral-faunal relationships for this species. The leafhopper Flexamia areolata sucks juices from the foliage of Purple Love Grass; the caterpillars of Poanes zabulon (Zabulon Skipper) also feed on the foliage. The foliage of young plants is palatable to cattle and other livestock.
Photographic Location: Along a railroad in Champaign, Illinois.
Comments: The large inflorescence is attractive, forming a purple haze in the distance. Purple Love Grass has spread throughout the state along roads and railways, but it is selective in the habitats that it invades. On moist fertile ground, taller grasses and forbs will displace this species. Compared to many other Eragrostis spp. (Love Grasses), Purple Love Grass has wider leaf blades (3-8 mm. across), an inflorescence that is longer than the rest of the plant, pedicels that are longer than the spikelets, and more showy purple spikelets. There is some variation in the size of the spikelets, lemmas and glumes; also, the hairiness of the foliage can be variable across different populations.