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Montana Field Guide

Montana Field Guides

Thickleaf Orach - Atriplex dioica
Other Names:  Atriplex subspicata, Atriplex patula var. subspicata


Global Rank: G4?
State Rank: SNR

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 3

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General Description
Monoecious annuals with sparsely farinose but still green foliage. Stems erect, 5–30 cm, branched from the base. Leaves sometimes opposite below, the blade 5–30 mm long, ovate to lanceolate, sometimes hastate, with mostly entire margins. Inflorescence terminal, short spikes of glomerules. Male flowers 4- to 5-parted. Female flowers lacking a calyx; pistillate bracts separate to near base. Mature pistillate bracts glabrous to sparsely farinose, ovate, 2–8 mm long, with a spongy, often tuberculate layer at the base. Lesica (2012) places our specimens in Atriplex subspicata, despite the explanation by Welsh (2003; Fl. N. Amer. Vol. 4) that the epithet "dioica" is an older name and thus has priority (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Present
 


Range Comments
In MT only in Beaverhead and Madison counties in the SW, and again in Valley and McCone counties in the northeast; AB, SK south to CA, NM, KS (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX). The distribution shown by Welsh (2003) for A. dioica is much wider than Lesica's inteprertation of A. subspicata.

Summary of Observations Submitted for Montana
Number of Observations: 8

(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
Drying mud around saline ponds, wetlands; valleys to montane (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

References
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Citation for data on this website:
Thickleaf Orach — Atriplex dioica.  Montana Field Guide.  .  Retrieved on , from