OregonFlora: Festuca roemeri

	Festuca roemeri
	Roemer's fescue
Habit	Plants 35–100 cm tall; densely cespitose, glaucous to green.
Culms	basal branching intravaginal.
Leaves	mainly basal; sheaths open, glabrous but sometimes hairy, not conspicuously splitting between the veins, usually pale, becoming gray-brown with age; collars glabrous; ligules 0.1–0.4 mm; blades 15–35 cm × 0.5–1.2(2.5)mm, conduplicate or occasionally flat; outer surface usually glabrous, sometimes hairy; inner surface glabrous, scabrous; hairy; flag leaves 7–12(18) cm.
Inflorescences	(8)10–20(25)cm; branches 3–7 cm, ascending to reflexed at anthesis, appressed after anthesis or sometimes the lowest spreading to reflexed.
Spikelets	9.5–12(13.5)mm, 3–6 florets.
Glumes	glabrous or scabrous to short-hairy at the tip only; lower glumes 2–5 mm, 1-veined; upper glumes 4–5.5(6.2)mm, 3-veined.
Caryopses	glabrous.
Ovaries	apex glabrous.
Leaf anatomy	cross sections usually 0.4–0.8 × 0.75–1.2 mm, elliptic or L-shaped; veins (5)7(10); ribs 5(9); dorsal sclerenchyma bands more than 2 times wider than thick, sometimes restricted to the midrib and margins only.
Lemmas	(5.8)6.5–8.2 mm, 0(5)-veined, with hairs on the distal part only; lemma awns 2–4(5)mm; shorter than or as long as the lemma body.
Anthers	3–5 mm.
2n	=28.

	Festuca roemeri
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	2 varieties. Festuca roemeri is most often confused with the bunchgrass forms of F. rubra. Festuca rubra leaves are smooth, the sheath margins are fused, and bunchgrass forms of F. rubra usually have shorter lemmas. In cross section, leaves of sterile shoots of F. rubra are diamond shaped to triangular, angled next to the largest lateral veins. The leaf sclerenchyma bands are less than twice as wide as thick. Festuca roemeri is closely related to F. idahoensis, and intermediate plants can be found where the ranges of the two species come into contact at the east end of the Columbia Gorge, in the High Cascades, and in Klamath County. Festuca idahoensis has round to hexagonal leaves that spin readily between one’s thumb and forefinger. Festuca roemeri leaves usually won’t roll, though leaves from very dry serpentine sites will roll but with the angles easily felt. Festuca trachyphylla and F. valesiaca have smaller lemmas and denser inflorescences. Vegetative F. valesiaca cannot be distinguished from F. roemeri.
Source	Flora of Oregon, volume 1, page 411 Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa	F. brachyphylla, F. californica, F. campestris, F. elmeri, F. filiformis, F. idahoensis, F. lemanii, F. occidentalis, F. rubra, F. saximontana, F. subulata, F. subuliflora, F. trachyphylla, F. valesiaca, F. viridula
Subordinate taxa	F. roemeri var. klamathensis, F. roemeri var. roemeri
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Festuca roemeri

Roemer's fescue

Habit

Plants 35–100 cm tall; densely cespitose, glaucous to green.

Culms

basal branching intravaginal.

Leaves

mainly basal;

sheaths open, glabrous but sometimes hairy, not conspicuously splitting between the veins, usually pale, becoming gray-brown with age;

collars glabrous;

ligules 0.1–0.4 mm;

blades 15–35 cm × 0.5–1.2(2.5)mm, conduplicate or occasionally flat;

outer surface usually glabrous, sometimes hairy;

inner surface glabrous, scabrous; hairy; flag leaves 7–12(18) cm.

Inflorescences

(8)10–20(25)cm;

branches 3–7 cm, ascending to reflexed at anthesis, appressed after anthesis or sometimes the lowest spreading to reflexed.

Spikelets

9.5–12(13.5)mm, 3–6 florets.

Glumes

glabrous or scabrous to short-hairy at the tip only;

lower glumes 2–5 mm, 1-veined;

upper glumes 4–5.5(6.2)mm, 3-veined.

Caryopses

glabrous.

Ovaries

apex glabrous.

Leaf anatomy

cross sections usually 0.4–0.8 × 0.75–1.2 mm, elliptic or L-shaped;

veins (5)7(10);

ribs 5(9); dorsal sclerenchyma bands more than 2 times wider than thick, sometimes restricted to the midrib and margins only.

Lemmas

(5.8)6.5–8.2 mm, 0(5)-veined, with hairs on the distal part only;

lemma awns 2–4(5)mm; shorter than or as long as the lemma body.

Anthers

3–5 mm.

=28.

Festuca roemeri

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

2 varieties.

Festuca roemeri is most often confused with the bunchgrass forms of F. rubra. Festuca rubra leaves are smooth, the sheath margins are fused, and bunchgrass forms of F. rubra usually have shorter lemmas. In cross section, leaves of sterile shoots of F. rubra are diamond shaped to triangular, angled next to the largest lateral veins. The leaf sclerenchyma bands are less than twice as wide as thick. Festuca roemeri is closely related to F. idahoensis, and intermediate plants can be found where the ranges of the two species come into contact at the east end of the Columbia Gorge, in the High Cascades, and in Klamath County. Festuca idahoensis has round to hexagonal leaves that spin readily between one’s thumb and forefinger. Festuca roemeri leaves usually won’t roll, though leaves from very dry serpentine sites will roll but with the angles easily felt. Festuca trachyphylla and F. valesiaca have smaller lemmas and denser inflorescences. Vegetative F. valesiaca cannot be distinguished from F. roemeri.