goat’s rue

(Tephrosia virginiana)

Conservation Status
goat’s rue
Photo by Nancy Falkum
  IUCN Red List

not listed

     
  NatureServe

N5 - Secure

S3 - Vulnerable

     
  Minnesota

Special Concern

     
           
           
           
           
           
           
 
Description
 
 

Goat’s rue is a showy summer wildflower. It occurs in the United States east of the Great Plains. It is rare in Minnesota, where it reaches the northwest extent of its range. It is restricted to a handful of counties in the extreme southeast, and is listed as a special concern species in the state. It is found in prairies, savannas, open woodlands, and roadsides. It grows under full or partial sun, in dry to moderately moist conditions, in sandy soil. Though infrequent, where it occurs it is often in large colonies.

Goat’s rue is an erect, perennial forb that rises on one to several stems from a thick, knobby base (caudex) and long woody roots. It can be 8 to 27½ (20 to 70 cm) tall but is usually no more than 20 (50 cm) in height. The plant is easy to identify when flowers or fruit are present, difficult to identify when they are not.

The stems are erect or curve up from the base (ascending) and are often clustered. They are usually unbranched but may have one or more weak branches. They are usually densely covered, sometimes moderately covered, with fine, appressed and spreading hairs.

The leaves are alternate, pinnately compound, and 2 to 6 long. There are usually 13 to 25 leaflets but there may be as few as 9 or as many as 31. At the base of each leaflet there is a pair of small, leaf-like appendages (stipules). Stipules on lower leaves are narrowly elliptic or lance-shaped to linear and ¼ to 716 (7 to 11 mm) in length. Those on upper leaves are often hairlike. They drop off early. The central axis (rachis) of the leaf is 1½ to 4¾ (4 to 12 cm) long.

The leaflets are narrowly elliptic to inversely lance-shaped, narrowly oblong, or linear, ½ to 1316 (12 to 30 mm) long, and 116 to (2 to 10 mm) wide. They are angled to rounded at the base and taper to a blunt or sharp point at the tip. The midvein of the leaflet usually continues to a needle-like point at the tip. The terminal leaflet is sometimes rounded or notched at the tip. The upper surface is medium green or grayish-green, and may be hairless or moderately to densely covered with short, fine, curved hairs. The lower surface is densely covered with appressed hairs. The lateral veins are noticeable on the underside. The margins are untoothed and usually have a fringe of ascending hairs.

The inflorescence is a short, dense, unbranched cluster (raceme) of 12 to 40 flowers at the end of the stem. The raceme is 1½ to 3 (4 to 8 cm) long and is on a to 1¼ (1 to 3 cm) long stalk. There are sometimes smaller racemes at the tips of the branches. Each flower is on a to ¾ (4 to 20 mm) long, densely hairy stalk (pedicel). At the base of each pedicel there is a single modified leaf (bract). The bract is 316 to ½ (6 to 12 mm) long, sometimes longer. It withers early but usually remains on the plant throughout the flowering and fruiting time.

Each flower is about ¾ long and wide. There are 5 outer floral leaves (sepals), 5 petals, 10 stamens, and 1 style. The sepals are light green, densely hairy, and fused for most of their length into a bell-shaped, 116 to 3 16 (2 to 5 mm) long tube (calyx), then separated into 2 lips, the upper lobe with 2 lobes, the lower lip with 3 lobes. The petals are organized into a typical pea-like arrangement, with an upper banner, a pair of lateral wing petals, and a pair of lower keel petals. The banner is to ¾ (15 to 19 mm) long, ½ to 1116 (12 to 18 mm) wide, broadly kidney-shaped to almost circular, and broadly pointed, rounded, or slightly notched at the tip. It is abruptly bent upward near the base and is keeled for its entire length. The outer surface is hairy. It is green at first, then turns yellow or cream-colored at maturity. The inner surface is white to cream-colored with a yellow patch near the base surrounded by a pink-tinged area. The wings are ½ to ¾ (12 to 20 mm) long, 316 to ¼ (5 to 7 mm) wide, rosy pink, oblong egg-shaped, and rounded at the tip. They are angled over and completely cover the keel. The keel is ½ to (12 to 15 mm) long and 316 to ¼ (5 to 7 mm) wide, boat-shaped, and curved upward at the tip. It is light pink or light yellow with a pink tinge or pink lines. Nine of the stamens have their stalks (filaments) fused together, one is free to below the middle. The anthers are small and yellow. The style is 516 to 716 (8 to 11 mm) long and has a minute stigma at the tip.

The fruit is a 1¼ to 2 (3 to 5 cm) long, to ¼ (3 to 6 mm) wide pod with 6 to 11 seeds. It is narrowly oblong, straight or slightly curved, and has a slender, often curved beak at the tip. The outer surface is sparsely to densely hairy, light green at first, becoming papery and straw-colored to brown at maturity. The seeds are kidney-shaped and to 316 long.

 
     
 

Height

 
 

8 to 27½ (20 to 70 cm)

 
     
 

Flower Color

 
 

Yellow or cream colored and rosy pink

 
     
 

Similar Species

 
 

Leadplant (Amorpha canescens), with its grayish-green leaflets, looks similar when flowers and fruit are not present. However, its leaflets are rounded to slightly heart-shaped at the base.

 
     
 
Habitat
 
 

Dry to moderately moist. Prairies, savannas, open woodlands, and roadsides. Full or partial sun. Sandy soil.

 
     
 
Biology
 
 

Flowering

 
 

Mid-June to late July

 
     
 

Pests and Diseases

 
 

 

 
     
 
Use
 
 

Toxicity

 
 

All parts of the plant are poisonous to both livestock and people.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 6, 24, 28, 29, 30.

 
  12/16/2021      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Rare in Minnesota

 
         
 
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 Rosanae  
 

Order

Fabales (legumes, milkworts, and allies)  
 

Family

Fabaceae (peas, legumes)  
 

Subfamily

Faboideae (Papilionoideae)  
 

Tribe

Millettieae  
 

Genus

Tephrosia (hoarypeas)  
       
 

Subordinate Taxa

 
 

 

 
       
 

Synonyms

 
 

Cracca latidens

Cracca virginiana

Tephrosia latidens

Tephrosia virginiana var. glabra

Tephrosia virginiana var. holosericea

 
       
 

Common Names

 
 

cagut

goat’s rue

goat’s-rue

rabbit-pea

Virginia tephrosia

 

 

 

 

 

 

 

 

Glossary

Ascending

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

 

Beak

On plants: A comparatively short and stout, narrow or prolonged tip on a thickened organ, as on some fruits and seeds. On insects: The protruding, tubular mouthpart of a sucking insect.

 

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. Plural: calyces.

 

Caudex

A short, thickened, woody, persistent enlargement of the stem, at or below ground level, used for water storage.

 

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.

 

Keeled

Folded, as in a grass blade, or with a raised ridge, as in a grass sheath; like the keel of a boat.

 

Linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass.

 

Pedicel

On plants: the stalk of a single flower in a cluster of flowers. On Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen.

 

Pinnate

Having the leaflets of a compound leaf arranged on opposite sides of a common stalk.

 

Raceme

An unbranched, elongated inflorescence with stalked flowers. The flowers mature from the bottom up.

 

Rachis

The main axis of a compound leaf, appearing as an extension of the leaf stalk; the main axis of an inflorescence.

 

Sepal

An outer floral leaf, usually green but sometimes colored, at the base of a flower.

 

Stigma

In plants, the portion of the female part of the flower that is receptive to pollen. In Lepidoptera, an area of specialized scent scales on the forewing of some skippers, hairstreaks, and moths. In other insects, a thickened, dark, or opaque cell on the leading edge of the wing.

 

Stipule

A small, leaf-like, scale-like, glandular, or rarely spiny appendage found at the base of a leaf stalk, usually occurring in pairs and usually dropping soon.

 

 

 

 

 
 
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Nancy Falkum

 
    goat’s rue   goat’s rue  
           
    goat’s rue      
           
 
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Other Videos
 
  Goat's Rue - Tephrosia virginiana
Eric Hunt
 
   
 
About

Sep 5, 2020

Video taken at the Camp Robinson Special Use Area Wildlife Management Area, Faulkner County, Arkansas

 
  Tephrosia virginiana Common Name(s): Goat's Rue Virginia Goat's Rue
ArkWildman survival
 
   
 
About

Jun 5, 2021

The seeds are toxic[222].

The plant contains rotenonoids and has been used traditionally as a fish poison - rotenoids kill or stun the fish making them easy to catch, but the fish remain perfectly edible for mammals. Rotenonoids are classified by the World Health Organization as moderately hazardous. They are mildly toxic to humans and other mammals, but extremely toxic to many insects (hence their use as an insecticide) and aquatic life, including fish. This higher toxicity in fish and insects is because the lipophilic rotenonoid is easily taken up through the gills or trachea, but not as easily through the skin or the gastrointestinal tract. The lowest lethal dose for a child is 143 mg/kg, but human deaths from rotenone poisoning are rare because its irritating action causes vomiting. Deliberate ingestion of rotenone, however, can be fatal.

 
  Goat's Rue
Kansas Land Trust
 
   
 
About

Jun 18, 2020

Kelly Kindscher talks about Goat's Rue on the Akin Prairie.

 

 

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  Nancy Falkum
6/17/2021

Location: Kellogg Weaver Dunes SNA, Weaver Dunes Unit

goat’s rue

 
           
 
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Created: 12/16/2021

Last Updated:

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