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Montana Field Guide

Montana Field Guides

Ballhead Sandwort - Arenaria congesta var. congesta
Other Names:  Eremogone congesta var. congesta

Global Rank: G5T5?
State Rank: SNR

Agency Status
MNPS Threat Rank:

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General Description
Perennial from a branched caudex, forming loose mats. Stems erect, simple, 5–30 cm. Leaves filiform, flexuous or rigid, glabrous, 2–8 cm long, shorter above. Inflorescence many-flowered, congested, glabrous; pedicels less than 0.5 mm long. Flowers: sepals glabrous, ovate to lanceolate, scarious-margined, 3–6 mm long, the tips rounded; petals oblong, 5–8 mm long. Capsules glabrous, 3–6 mm long (adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Diagnostic Characteristics
Variety congesta has capitate, congested flowers in the inflorescence and sepals with obtuse to rounded apices.

Species Range

Range Comments
WA and MT south to CA and AZ; most abundant in the Rocky Moutains and northern Great Basin (Kartesz 2009).

Summary of Observations Submitted for Montana
Number of Observations: 7

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



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

Gravelly or sandy soil of plains, mountain slopes, and ridges (Hartman et al., 2005, Fl. North America, Vol. 5).

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Citation for data on this website:
Ballhead Sandwort — Arenaria congesta var. congesta.  Montana Field Guide.  .  Retrieved on , from