western rock jasmine

(Androsace occidentalis)

Conservation Status
western rock jasmine
 
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

FACU - Facultative upland

     
  Midwest

FACU - Facultative upland

     
  Northcentral & Northeast

UPL - Obligate upland

     
           
 
Description
 
 

Western rock jasmine is a small annual forb that appears as a basal rosette of leaves and several flowering stalks rising from a slender taproot. It occurs throughout western and central North America. It is most common between the Rocky Mountains and the Mississippi River. In Minnesota it is occasional in the western, southern, and central regions, absent from the northeast. It is short-lived, flowering from April to May and dying back by mid-summer. It is easily overlooked due to its diminutive size. For these reasons it may be more common than reported.

Western rock jasmine does not form mats. Numerous leaves form a single inconspicuous, radiating cluster (rosette) on or close to the ground. The leaves are lance-shaped to egg-shaped, 3 16 to ¾ (5 to 20 mm) long, and to (4 to 9 mm) wide. They are on minute leaf stalks. The leaf blades are green, sometimes reddish-green toward the tip, rarely entirely red. They are tapered to the base and taper to a narrowly rounded tip. The upper surface is covered with short, fine, soft, unbranched, grayish-white hairs. The lower surface is hairless. The margins are hairy and may be untoothed or have shallow, blunt teeth toward the tip.

There is no true stem. Rising from the center of the basal rosette are usually 3 to 15, sometimes just 1 or 2, long flower stalks (scapes). The inner scapes are more or less erect, the outer are curved upward from the base (ascending). The scapes can be 13 16to 4 (3 to 10 cm) long, but are is usually no more than 3 (7 cm) in length. They are unbranched, leafless, and covered with minute, fine, soft, branched hairs. They may be green, greenish-red, or entirely red.

At the end of each scape there is sometimes a single flower but usually an umbrella-shaped cluster (umbel) of 2 to 10 or more flowers. Each umbel is subtended by a whorl (involucre) of up to 10 modified leaves (bracts). The bracts are relatively broad, lance-shaped to elliptic or egg-shaped, (3 to 4 mm) long, and 1 16 (1.5 to 2.0 mm) wide. The rays of the umbel (pedicels) are slender, finely hairy, and to 13 16 (10 to 30 mm) long. The pedicels are unequal in length. The inner ones are more or less straight, the outer ones are ascending.

The flowers are about 1 16 (2 mm) wide and 1 16 to (2 to 4 mm) long. There are 5 sepals, 5 petals, 5 stamens, and 1 style. The sepals (calyx) are green, minutely hairy, and to ¼ (3 to 6 mm) long. They are fused at the base for less than half their length into a ridged, broadly bell-shaped cup, then separated into five erect, broadly lance-shaped lobes. The petals (corolla) are white and 1 16 to (2 to 4 mm) long. They are fused at the base into a floral tube that is shorter than or equal to the calyx, then separated into 5 ascending to spreading lobes. The lobes are shorter than the floral tube. The stamens have very short stalks (filaments) and do not protrude from the corolla.

The fruit is an oval, to 3 16 long capsule containing 20 to 50 dark brown seeds. The petals are persistent in fruit, the tips remaining white, even after the capsule has been shed.

 
     
 

Height

 
 

13 16to 4 (3 to 10 cm)

 
     
 

Flower Color

 
 

White

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Moderately moist to dry. Upland prairies with sand, gravel, or rocky debris; hillsides; ravines; cliffs; old fields; railroads; roadsides; and disturbed areas. Full sun.

 
     
 
Biology
 
 

Flowering

 
 

April to May

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 28, 29, 30.

 
  11/4/2019      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

In Minnesota, absent in northeast, occasional elsewhere.

 
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  
 

Order

Ericales (heathers, balsams, primroses, and allies)  
 

Family

Primulaceae (primrose)  
  Subfamily Primuloideae  
  Tribe Androsaceeae  
 

Genus

Androsace (rock jasmine)  
       
 

Subordinate Taxa

 
       
       
 

Synonyms

 
 

Androsace arizonica

Androsace occidentalis var. arizonica

Androsace occidentalis var. simplex

 
       
 

Common Names

 
 

western rock jasmine

western rock-jasmine

western rockjasmine

 
       

 

 

 

 

 

 

 

 

Glossary

Ascending

Growing upward at an angle or curving upward from the base.

 

Bract

Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.

 

Calyx

The group of outer floral leaves (sepals) below the petals, occasionally forming a tube.

 

Corolla

A collective name for all of the petals of a flower.

 

Filament

On plants: The thread-like stalk of a stamen which supports the anther. On Lepidoptera: One of a pair of long, thin, fleshy extensions extending from the thorax, and sometimes also from the abdomen, of a caterpillar.

 

Involucre

A whorl of bracts beneath or surrounding a flower or flower cluster.

 

Pedicel

On plants: the stalk of a single flower in a cluster of flowers. On insects: the second segment of the antenna. On Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen: the preferred term is petiole.

 

Rosette

A radiating group or cluster of leaves usually on or close to the ground.

 

Scape

On plants: An erect, leafless stalk growing from the rootstock and supporting a flower or a flower cluster. On insects: The basal segment of the antenna.

 

Umbel

A flat-topped or convex, umbrella-shaped cluster of flowers or buds arising from more or less a single point.

       
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Inflorescence

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Flowers

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Rosette of Basal Leaves

  western rock jasmine    

Infructescence

  western rock jasmine    
       
       

 

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Created: 11/4/2019

Last Updated:

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