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Montana Field Guide

Montana Field Guides

Caespitose Rockmat - Petrophytum caespitosum
Other Names:  Petrophyton caespitosum


Global Rank: G5
State Rank: S5
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value:

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State Rank Reason (see State Rank above)
Very common on calcareous rocks in Montana and elsewhere. A widely ranging species in the interior west. Rare in some outlying stations, but common in its core range.
 
General Description
Mat-forming shrub. Stems branched, prostrate, clothed in old leaf bases; erect stems scapose, 3–10 cm. Leaves basal and cauline, exstipulate, short-petiolate, oblanceolate, glabrate to sericeous, entire, 3–12 mm long; cauline reduced, bract-like. Inflorescence a dense, cylindrical raceme, 1–4 cm long. Flowers perfect, 5-merous, perigynous; hypanthium cup-shaped, sericeous; sepals 1–2 mm long, deltoid; petals white, 1.5–2.5 mm long; stamens 20 to 40; styles usually 5. Fruit a 1- to 2-seeded follicle, ca. 3 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Present
 


Range Comments
OR to SD, south to CA, AZ, NM, TX and Mexico (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 32

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Crevices of cliffs and rock outcrops, usually on limestone; montane to alpine (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

References
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Citation for data on this website:
Caespitose Rockmat — Petrophytum caespitosum.  Montana Field Guide.  .  Retrieved on , from