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Montana Field Guide

Montana Field Guides

Western Centaury - Centaurium exaltatum
Other Names:  Zeltnera exaltata

Potential Species of Concern

Global Rank: G5
State Rank: SH
* (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)
Known from one 1890 collection with imprecise location data from Big Horn County, "seven miles south of Custer Station".
 
General Description
Western Centaury is an annual herb with usually unbranched stems that are 5-25 cm high. The basal leaves are lance-shaped to narrowly elliptic and 5-25 mm long, while those of the stem are longer and narrower. The leaves lack petioles and are opposite each other on the stem. Foliage is glabrous. One to a few erect flowers are borne on 1-4 cm long stalks 1-4 at the top of the stems. The white to light pink flowers have a slender, lobed calyx, 6-9 mm long, which tightly encloses a tubular corolla that flares at the top into 5 spreading petals that are ca. 4 mm long. The 5 stamens are exserted from the corolla tube. The fruit is a slender capsule nearly twice the length of the calyx at maturity.

Phenology
Flowering in August.

Diagnostic Characteristics
Members of the Gentian Family have opposite leaves, glabrous foliage, and tubular corollas with 4-5 equal lobes. Centaurium exaltatum can be distinguished from other members of the family by its long, narrow corolla tube and by its lack of membranous tissue between the calyx lobes. A hand lens may be necessary for positive determination.

Species Range
Unknown/Undetermined
 


Range Comments
BC and eastern WA to MT, south to CA, CO, and NE. Sparse.

Summary of Observations Submitted for Montana
Number of Observations: 1

(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
Moist alkaline soil around ponds and streams on the plains.

References
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Citation for data on this website:
Western Centaury — Centaurium exaltatum.  Montana Field Guide.  .  Retrieved on , from