OregonFlora: Lolium perenne vs. Poaceae tribe Poeae

	Lolium perenne	Poaceae tribe Poeae
	perennial ryegrass
Habit	Plants long-lived perennials, to 100 cm tall; cespitose; with vegetative shoots at flowering and fruiting time.
Leaves	sheaths open; blades usually 10–30 cm × (1)2–4(6) mm, folded in the bud.
Inflorescences	spikes, 3–30 × 0.5–1.2 cm, 5–37 spikelets; main axis 0.5–2.5 mm thick at the nodes, often flexuous.
Spikelets	5–22 × 1–7 mm; (2)5– 9(10) florets.
Glumes	3.5–15 mm, 50–75% as long as the spikelet, rarely slightly exceeding it, membranous to somewhat hard.
Caryopses	3–5.5 × 0.7–1.5 mm, 3 or more times longer than wide.
Lemmas	3.5–9 × 0.8–2 mm; awnless or awned; lemma awns 0–8 mm, attached 0.2–0.7 mm below the lemma tip.
Anthers	2–4.2 mm.
2n	=14.

	Lolium perenne	Poaceae tribe Poeae
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Disturbed open areas, meadows, roadsides. 0–1300m. Casc, Col, CR, Est, Lava, Sisk, WV. CA, ID, NV, WA; throughout North America; temperate regions worldwide. Exotic. Typical L. perenne is perennial with remnants of last year’s leaves at the base, few florets, and awnless or short-awned lemmas. Typical L. multiflorum is annual with many florets per spikelet and awned lemmas. The two species hybridize and intergrade. Plants that combine traits of both species can be called L. × hybridum. Alternatively, the closely related L. perenne and L. multiflorum might be treated as subspecies within L. perenne.
Source	Flora of Oregon, volume 1, page 429 Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa	L. multiflorum, L. rigidum, L. temulentum
Synonyms	Festuca perennis, Lolium perenne var. cristatum
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	Google search

Poaceae tribe Poeae

perennial ryegrass

Habit

Plants long-lived perennials, to 100 cm tall; cespitose; with vegetative shoots at flowering and fruiting time.

Leaves

sheaths open;

blades usually 10–30 cm × (1)2–4(6) mm, folded in the bud.

Inflorescences

spikes, 3–30 × 0.5–1.2 cm, 5–37 spikelets; main axis 0.5–2.5 mm thick at the nodes, often flexuous.

Spikelets

5–22 × 1–7 mm; (2)5– 9(10) florets.

Glumes

3.5–15 mm, 50–75% as long as the spikelet, rarely slightly exceeding it, membranous to somewhat hard.

Caryopses

3–5.5 × 0.7–1.5 mm, 3 or more times longer than wide.

Lemmas

3.5–9 × 0.8–2 mm; awnless or awned;

lemma awns 0–8 mm, attached 0.2–0.7 mm below the lemma tip.

Anthers

2–4.2 mm.

=14.

Poaceae tribe Poeae

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Disturbed open areas, meadows, roadsides. 0–1300m. Casc, Col, CR, Est, Lava, Sisk, WV. CA, ID, NV, WA; throughout North America; temperate regions worldwide. Exotic.

Typical L. perenne is perennial with remnants of last year’s leaves at the base, few florets, and awnless or short-awned lemmas. Typical L. multiflorum is annual with many florets per spikelet and awned lemmas. The two species hybridize and intergrade. Plants that combine traits of both species can be called L. × hybridum. Alternatively, the closely related L. perenne and L. multiflorum might be treated as subspecies within L. perenne.