Species Details

Poa rhizomata

timber blue grass

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Species Description:

Poa rhizomata, commonly known as timber blue grass, is a perennial rhizomatous herb in the Poaceae that is found in California and elsewhere. It occurs within Lower montane coniferous forest, Subalpine coniferous forest, and Upper montane coniferous forest, growing at elevations from 520 to 2040 meters. Poa rhizomata is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification

Scientific Name: Poa rhizomata Hitchc.
Common Name: timber blue grass
Family:	Poaceae
Element Code:	PMPOA4Z250
USDA Plants Symbol:	PORH
Synonyms/Other Names:
Name Status:	JEP, FNA, POWO, IPNI, Tropicos

Conservation Status

CA Rare Plant Rank:	1B.3
Fed List:	None
State List:	None
Global Rank:	G3G4
State Rank:	S3S4
Other Status:
CRPR Changes: changed from 4.3 to 1B.3 on 2024-02-01
Add Date:	1974-01-01
Date Edited:	2024-08-06

Ecology and Life History

Lifeform: perennial rhizomatous herb

Blooming Period: Apr-Jul

Elevation:
520 - 2040 meters
1705 - 6695 feet

General Habitats:

Lower montane coniferous forest
Subalpine coniferous forest
Upper montane coniferous forest

Microhabitat Details: Semi-shaded moist slopes, small openings in forest

Microhabitat:

Mesic
Serpentine (sometimes)

Notes

Notes: Extremely rare and threatened in OR.
Threats: Potentially threatened by logging, inappropriate grazing, trampling, and fire changes in fire regime.
Taxonomy: Plants on ultramafic substrates in DNT Co. are referable to Poa piperi (previously treated as a taxonomic synonym of P. rhizomata). Other similar species are P. pratensis (nonnative naturalized in CA) and P. chambersii (OR endemic).

Threat List Data from the CNDDB

THREAT LIST:
Threat List Total:	3
	Total EOs	% of EOs
EOs with Threat Listed:	2	13 %
Foot traffic/trampling	1	6%
Grazing	1	6%
Logging	1	6%

Occurrence Data from the CNDDB

Element Occurrence Ranks:
Total Occurrences:					16
A	B	C	D	X	U
0	2	0	0	0	14

Occurrence Status:
Historical >20 Years	14
Recent <=20 Years	2

Presence:
Presumed Extant	16
Possibly Extirpated	0
Presumed Extirpated	0

Location

California Endemic:

California Island:

States: Name (Code)
California (CA), Oregon (OR)

California Counties and Islands: Name (Code)
Shasta (SHA), Siskiyou (SIS), Trinity (TRI)

Quads: Name (Quad Code)
Bark Shanty Gulch (4112345), Billys Peak (4112227), Callahan (4112237), Chicken Hawk Hill (4112214), Condrey Mtn. (4112288), Cottonwood Peak (4112286), Dillon Mtn. (4112355), Eaton Peak (4112238), Etna (4112248), Greenview (4112258), Horse Creek (4112278), Kangaroo Mtn. (4112382), McKinley Mtn. (4112277), Somes Bar (4112344), Ukonom Lake (4112353), Ukonom Mtn. (4112354), Ycatapom Peak (4112217)

Notes:

Definitions of codes following a county and/or quad:
*		Presumed extirpated
(?)		Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.

Regional Map

Map

Presumed Extant

Click on quad for name. Hold Shift Key to use mouse scroll wheel

CNPS Status Review:	Poa rhizomata Proposed Change from CRPR 4.3 to 1B.3 (2024)
Original Description:	Flora of California [Jepson] 1(3): 155 (1912)
Species Account:	USFS Potential Species of Conservation Concern Profile (2021)

CNPS Rare Plant Inventory