black locust

(Robinia pseudoacacia)

Conservation Status
black locust
Photo by Randy
  IUCN Red List

LC - Least Concern

     
  NatureServe

N5 - Secure

SNA - Not applicable

     
  Minnesota

not listed

     
           
Weed Status
   
 

Invasive

     
           
Wetland Indicator Status
     
  Great Plains

UPL - Obligate upland

     
  Midwest

FACU - Facultative upland

     
  Northcentral & Northeast

FACU - Facultative upland

     
           
 
Description
 
 

Black locust is a medium-sized, fast-growing, short-lived, deciduous tree rising on a single trunk from a shallow, wide-spreading root system. It can be 30 to 100 in height and 12 to 40in diameter at breast height, though in Minnesota mature trees are usually no more than 60 tall and 6in diameter. It reproduces by seed and spreads aggressively by suckers. It often forms thickets.

The trunk is often crooked. The crown is narrow, open, and irregular. The branches are spreading to ascending, short, crooked, and brittle.

The bark on young trees is smooth and gray or brown. On mature trees the bark is gray or brown, thick, and separated into long, forking ridges and deep furrows.

First-year twigs are light green and slightly hairy. Second-year twigs are slender, brittle, brown or reddish-brown, and hairless, with scattered lenticels. There is a pair of spines at each node. The spines are broad-based, sharp, and ½ to 1 long. The leaf scars are triangular to 3-lobed. They have 3 bundle scars and often 3 irregular cracks.

There are no terminal buds. Lateral buds are tiny, hairy, and not easy to see. Clusters of 3 or more buds are concealed in the leaf scar beneath the base of the leaf.

The leaves are alternate, deciduous, and 3 to 8 long. They are pinnately divided into 7 to 19 leaflets. They are on to 1 long, sparsely to moderately hairy leaf stalks.

The leaflets are elliptical to oblong, ¾to 2 long, and to 13 16 wide. They are rounded at the base and rounded or blunt at the tip. The leaf tip is occasionally slightly notched and has a short, sharp, abrupt point. The upper surface is dark green, not shiny. The lower surface is pale green and is usually sparsely covered with short, appressed hairs. The margins are untoothed.

The inflorescence is a drooping, unbranched cluster (raceme) rising from upper leaf axils of current-year branches. Each raceme is 2 to 5 long and has 8 to 30 flowers.

Individual flowers are ¾ to 1 long and white. They are on on 3 16 to long, hairy stalks. The 5 green, finely hairy sepals are fused for most of their length into a bell-shaped, to 5 16 long tube (calyx), then separated into 5 shallow lobes.

The 5 petals are butterfly-like, as is typical of plants in the Pea family. They are organized into a banner petal, two wing petals, and two fused keel petals. The banner is upright and bent backward along both sides. The wings are straight and project forward. The keel is curved upward. There are 10 stamens and a single style. The flowers are strongly scented.

The fruit is a drooping, narrowly oblong, flat, hairless seedpod containing 2 to 10 seeds. It is 13 16 to 4 long, to 1 wide. It is green at first, turning brown as it ripens. The pod matures early August to early September.

 
     
 

Height

 
 

30 to 60

 
     
 

Record

 
 

Records are not kept for nonnative species.

 
     
 

Flower Color

 
 

White

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Moist. Forest borders and openings. Shade intolerant.

 
     
 
Biology
 
 

Flowering

 
 

Mid-May to mid-July

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 8, 24, 28, 30.

 
  11/2/2018      
         
 

Nativity

 
 

Native to Pennsylvania, West Virginia, Illinois, Missouri, Oklahoma, Georgia, and Kentucky. Introduced and naturalized in Minnesota.

 
         
 

Occurrence

 
 

 

 
         
 
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 (dicots)  
  Subclass Rosidae  
  Superorder Rosanae  
 

Order

Fabales (legumes, milkworts, and allies)  
 

Family

Fabaceae (peas, legumes)  
  Subfamily Faboideae (Papilionoideae)  
  Tribe Robinieae  
  Genus Robinia (locust)  
       
 

Synonyms

 
 

Robinia pseudo-acacia

Robinia pseudoacacia f. inermis

Robinia pseudoacacia var. pyramidalis

Robinia pseudoacacia var. rectissima

 
       
 

Common Names

 
 

black locust

false acacia

yellow locust

 
       

 

 

 

 

 

 

 

 

 

 

 

Glossary

Axil

The upper angle where a branch, stem, leaf stalk, or vein diverges.

 

Calyx

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

 

Lenticel

A corky, round or stripe-like, usually raised, pore-like opening in bark that allows for gas exchange.

 

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.

 

Sepal

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

 

Sucker

A basal shoot rising from the roots or from a bud at the base of a shrub or tree.

       
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Randy
       
  black locust   black locust
       
  black locust   black locust
       
MinnesotaSeasons.com Photos
   

Plant

  black locust   black locust
       
  black locust   black locust
       

Leaves

  black locust   black locust
       

Stem

  black locust   black locust
       
  black locust    
       

Infructescence

  black locust    
       

Fruit

  black locust    
       
       

 

Camera

     
Slideshows
   
  Robinia pseudoacacia
Blake C. Willson
 
  Robinia pseudoacacia  
 
About

Black Locust

 
     
  Black Locust
DianesDigitals
 
  Black Locust  
 
About

Copyright DianesDigitals

 
     
  Robinia pseudoacacia - Black Locust
Virens (Latin for greening)
 
  Robinia pseudoacacia - Black Locust  
 
About

Leguminosae - Pea Family (alt. Fabaceae - Bean Family)

ECOLOGICAL THREAT
Robinia pseudoacacia - Black locust poses a serious threat to native vegetation ecosystems outside of its historic North American range.

NATIVE RANGE
Southeastern United States and other separate outliers.

Source: Plant Conservation Alliance, Alien Plant Working Group
www.nps.gov/plants/alien/fact/rops1.htm

 
     
  Black Locust (Robinia pseudoacacia)
Andree Reno Sanborn
 
  Black Locust (Robinia pseudoacacia)  
 
About

Prohibited in Massachusetts and Connecticut.
Invasive.

 
     
  Black Locust (Robinia pseudoacacia)
Bill Keim
 
  Black Locust (Robinia pseudoacacia)  
     
  Black locust (Robinia pseudoacacia)
Jim Hamilton
 
   
 
About

Uploaded on Jun 18, 2008

Species information for black locust.

 
     

 

slideshow

       
Visitor Videos
       

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Other Videos
 
  The Black Locust
oneminuteenvironment
 
   
 
About

Uploaded on Jul 9, 2011

The Black Locust (Robinia pseudoacacia) ranks among the 40 worst invasive tree species in the world. In 1601 its first seeds were sent from the Americas to France. Since then it has made its way into gardens in Africa, Asia and Australia. Unfortunately it also spreads readily into the wild where it overgrows all native vegetation.

Watch this related video on mail order invasions: http://www.youtube.com/user/oneminuteenvironment#p/c/DD15212D18439CD0/4/JRZKvSQOKqE

   
       
  Comparing toxic Black Locust pod and an edible Honey Locust pod
zuditaka
 
   
 
About

Uploaded on Nov 21, 2011

Many people on YouTube, including some nursery owners (who should know better!), cannot tell the difference between a toxic Black Locust pod and an edible Honey Locust pod.

Just a quick look, in the garden, today, at the difference between Black Locust pods and Honey Locust pods. You can see that the Black Locust pods are only tiny in comparison to the giant (brown-coloured) Honey Locust pods. There is also a leaf difference, too. The Gleditsias have smaller leaves and the Robineas have larger leaves.

Disclaimer:
This video is for entertainment purposes only. Always seek the advice of botanists, medical and wild food experts before ever ingesting any wild or foraged foods.

   
       
  Trees with Don Leopold - black locust
ESFTV
 
   
 
About

Uploaded on Oct 21, 2011

No description available.

   
       
  Black Locust identification video
wvoutdoorman
 
   
 
About

Published on Aug 6, 2012

Black Locust identification (Robinia Pseudoacacia). It is the tree for fence post because the wood last forever.

   
       
  Black Locust Tree (rev 5-11)
ondeerpath
 
   
 
About

Uploaded on May 29, 2011

No description available.

   
       

 

Camcorder

         
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Randy
7/19/2016

Location: Albert Lea, MN

Black locust in Albert Lea

plains cottonwood


     
     
 
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