OregonFlora: Agrostis densiflora

	Agrostis densiflora
	California bentgrass
Habit	Plants perennial, 9–85 cm tall; cespitose, occasionally rhizomatous when buried by moving sand.
Leaves	ligules 1–3(7.5)mm; dorsal surfaces scabrous, membranous; blades 2–12 cm × 2–10 mm; flat; upper blades wider than lower blades.
Inflorescences	2–10 × 0.5– 2 cm; narrow; dense; ellow-green, sometimes tinged with purple, bases often enclosed in the upper sheaths at maturity; branches appressed; to 1.5 cm, mostly hidden by the spikelets.
Glumes	2–3.3 mm, 1-veined, densely scabrous over the back, strongly scabrous on the veins; tips narrowly acute to acuminate or mucronate.
Calluses	hairs to 0.3 mm; the hairs usually dense.
Lemmas	1.5–2.1 mm; (3)5-veined; veins extended as teeth to 0.3 mm; tips acute to obtuse, sometimes toothed; awnless or awned; lemma awns 0–3.5 mm, arising from above mid-length; straight, readily falling off.
Paleas	(0.3)0.5–0.7 mm.
Anthers	0.3–0.7 mm.
2n	=42.

	Agrostis densiflora
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Sandy soils on coastal dunes and bluffs. 0–50 m. Est. CA. Native. With its dense inflorescence, A. densiflora can be confused with A. exarata and coastal forms of A. pallens. Agrostis exarata usually has shorter paleas and longer ligules, although there is considerable overlap in these characters. Agrostis pallens is usually strongly rhizomatous, its anthers are more than 1 mm, its inflorescence is exserted from the upper leaf sheaths, and it usually has narrower leaves.
Source	Flora of Oregon, volume 1, page 351 Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa	A. canina, A. capillaris, A. castellana, A. exarata, A. exarata x Agrostis pallens, A. exarata x Agrostis stolonifera, A. gigantea, A. hallii, A. hallii x Agrostis pallens, A. hendersonii, A. howellii, A. idahoensis, A. microphylla, A. oregonensis, A. pallens, A. scabra, A. stolonifera, A. variabilis
Web links	Local floras: CA, OR 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

Agrostis densiflora

California bentgrass

Habit

Plants perennial, 9–85 cm tall; cespitose, occasionally rhizomatous when buried by moving sand.

Leaves

ligules 1–3(7.5)mm; dorsal surfaces scabrous, membranous;

blades 2–12 cm × 2–10 mm; flat; upper blades wider than lower blades.

Inflorescences

2–10 × 0.5– 2 cm; narrow; dense; ellow-green, sometimes tinged with purple, bases often enclosed in the upper sheaths at maturity;

branches appressed; to 1.5 cm, mostly hidden by the spikelets.

Glumes

2–3.3 mm, 1-veined, densely scabrous over the back, strongly scabrous on the veins;

tips narrowly acute to acuminate or mucronate.

Calluses

hairs to 0.3 mm; the hairs usually dense.

Lemmas

1.5–2.1 mm; (3)5-veined;

veins extended as teeth to 0.3 mm;

tips acute to obtuse, sometimes toothed; awnless or awned;

lemma awns 0–3.5 mm, arising from above mid-length; straight, readily falling off.

Paleas

(0.3)0.5–0.7 mm.

Anthers

0.3–0.7 mm.

=42.

Agrostis densiflora

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Sandy soils on coastal dunes and bluffs. 0–50 m. Est. CA. Native.

With its dense inflorescence, A. densiflora can be confused with A. exarata and coastal forms of A. pallens. Agrostis exarata usually has shorter paleas and longer ligules, although there is considerable overlap in these characters. Agrostis pallens is usually strongly rhizomatous, its anthers are more than 1 mm, its inflorescence is exserted from the upper leaf sheaths, and it usually has narrower leaves.

Source

Flora of Oregon, volume 1, page 351
Barbara Wilson, Richard Brainerd, Nick Otting

Sibling taxa