Vulpia octoflora tenella
Grass family (Poaceae)
Description: This native grass is a summer annual that consists of a small tuft of leafy culms about 6-18" tall. The culms are terete, hairless, and light green, light tan, or light purple; they are often decumbent at the base and sparingly branched. At maturity, each culm has 1-3 alternate leaves along its length (excluding withered lower leaves). The blades of these leaves are up to 8" long and 2.0 mm. across; they are light green, hairless, and somewhat involute (curving inward along the midrib). Each leaf blade is ascending or erect near the base, curving outward from the culm; each blade has a very slender tip. The leaf sheaths are light green, finely veined, and hairless; they become purplish/reddish and somewhat loose with age. The ligules are membranous, while the nodes are glabrous and slightly swollen. Each culm terminates in a narrow panicle of spikelets up to 6" long and 1½" across. The central axis (rachis) of this inflorescence and its branches are light green and rough-textured; the branches are up to 3" long, straight, and erect to slightly spreading. The spikelets are evenly spaced and appressed along the length of each branch. Each spikelet is 11-13 mm. long, 1.5-2.0 mm. across, and somewhat flattened; it has a pair of glumes and 5-9 lemmas in 2 columnar ranks. Each spikelet has a short pedicel, or it is sessile. The glumes are unequal in size: the smaller glume is 3.0-3.5 mm. in length and linear in shape, while the large glume is 4.0-6.0 mm. in length and lanceolate-linear in shape. The lemmas are 3.5-5.0 in length (excluding their awns), linear-lanceolate in shape, and light green to black (sometimes tinted red or purple); their awns are 1.0-3.0 mm. in length. The blooming period occurs during the summer. Some florets fail to produce exerted stamens and styles, but they are self-fertile. Disarticulation is above the glumes. Each fertile lemma produces a single grain. The root system is coarsely fibrous and shallow. This grass spreads by reseeding itself; it occasionally forms sizable colonies.
Cultivation: This weedy grass prefers full sun, dry conditions, and barren soil containing sand or gravel.
Range & Habitat: Six-Weeks Fescue is occasional to locally common throughout Illinois (see Distribution Map). The records for the typical variety, var. tenella, and var. glauca have been combined in this map. Among these varieties, the typical variety and var. tenella (described above) are about equally common in Illinois, while var. glauca is less common and restricted to southern Illinois. Habitats consist of dry upland prairies (including hill prairies, gravel prairies, & sand prairies), rocky glades, thinly wooded rocky slopes, sandy or gravelly areas along railroads, abandoned fields, and barren waste areas. This grass is often found in disturbed areas and degraded natural habitats.
Faunal Associations: Records of floral-faunal associations for this species are mainly from the Western states. The foliage of this grass is occasionally eaten by Arphia conspera (Speckled-Winged Grasshopper). Vertebrate animals that may use Six-Weeks Fescue as a food plant include upland gamebirds (seeds), sparrows (seeds), mice (seeds or foliage), rabbits (mainly foliage), and pocket gophers (mainly foliage).
Photographic Location: A barren area along a railroad in Champaign, Illinois.
Comments: At one time, Six-Weeks Fescue was classified as Festuca octoflora. This grass and other annual Festuca spp. have been reassigned to the Vulpia genus. These other species occur mainly in the Western states and their spikelets have longer awns than those of Six-Weeks Fescue. In general, these drought-adapted grasses have slender leaves and a short stature. Six-Weeks Fescue is rather variable across its range and different varieties have been described. The typical variety differs from var. tenella (described above) by having spikelets with longer awns (> 3 mm.), while var. glauca has spikelets without awns or shorter ones (< 2 mm.); also the smaller glumes of var. glauca are shorter (< 3 mm.) than those of var. tenella. Sometimes the lemmas of the typical variety and var. tenella are slightly pubescent, rather than hairless. However, this is difficult to observe without a 10x hand lens.