Kentucky coffee tree

(Gymnocladus dioicus)

               
Conservation Status

IUCN Red List

not yet assessed

Kentucky coffee tree

NatureServe

N5? - Secure

SNR - Unranked

Minnesota

Special Concern

Nativity

Native to Wisconsin, Iowa, and South Dakota

Occurrence

Uncommon or rare

Habitat

Moist to moderately moist. River terraces above the flood plain. Full sun. Not shade tolerant. Well drained soil.

Flowering

Late May to late June

Flower Color

greenish-white

Height

50 to 70

Photo by Randy

Identification

This is a medium-sized, moderate-growing, deciduous tree that rises on a single trunk from a fibrous root system. In Minnesota mature trees are usually 50 to 70 tall and up to 24 in diameter at breast height, though large individuals can reach over 80 in height and 29 in diameter. It is moderately long-lived, often lasting 75 years, though healthy individuals on favorable sites may survive 100 to 150 years. It spreads by root suckering, often forming interconnected colonies. Unlike most plants in the Pea (Fabaceae) family, the roots do not have nodules.

When growing in open areas the trunk is short, straight, and stout. It usually splits into three or four stout, ascending, principal branches about 10 to 15 above the ground. The crown is rounded and open. The branches are coarse, crooked, and widely spreading or weakly ascending. In forested areas the trunk is longer, the crown is narrow and pyramidal, and there are fewer, shorter branches.

The bark on young trees is light brown and smooth. It quickly breaks into conspicuous, large, flaky scales. On mature trees the bark is silvery gray, often tinged reddish, thick, and shallowly grooved, with scaly ridges that curl outward at the edges. On older trees the bark is dark gray and thick with shallow fissures and flat ridges.

The twigs are widely spaced and very stout. They are not noticeably zigzag. They are grayish-brown with whitish patches, hairless, and covered with scattered orange or pale dots (lenticels). The pith is large. homogeneous (not spongy), and orangish-red. The leaf scars are large, broad, and more or less heart-shaped. They have 3 or 5 large bundle scars.

The tip of the twigs are tapered to a blunt point and there are no terminal buds. Lateral buds are small, inconspicuous, ¼ to long, and bronze. They appear in groups of 2 or 3 above the leaf scars. They are deeply sunken in raised craters that are filled with silky hairs.

The leaves appear in mid-spring before the flowers. They are the largest leaves of any tree in Minnesota. They are also the latest to appear in the spring and one of the first to drop in autumn. They are deciduous, alternate, 12 to 36 long, up to 24 wide, and bipinnately compound with 40 to 100 leaflets. They are on stout, 4 to 8 long, hairless leaf stalks. They are pinnately divided into 4 to 7 primary divisions (pinnae), each with 4 to 6 pairs of leaflets. The lowest pair of pinnae are sometimes replaced with a pair of leaflets.

The leaflets are alternate, egg-shaped to broadly elliptic, ¾ to 3½ long, and to 2 wide. They are usually rounded, sometimes broadly angled, at the base, and taper to a point at the tip, usually with straight sides along the tip, sometimes concave very near the tip. The upper surface is medium or dark green and hairless. The lower surface is pale green and finely hairy, at least along the veins. The margins are untoothed and have an inconspicuous fringe of short hairs. In early autumn the leaves turn yellowish-gold before dropping.

Male and female flowers are usually borne on the separate trees. Sometimes a tree with flowers of one gender will have some inflorescences with both flowers of that gender and bisexual (perfect) flowers. They appear when the leaves are unfolded in late May to late June. The inflorescence is a 2¾ to 8 long, ascending or spreading, unbranched array (raceme) of 18 to 50 flowers at the end of a short branch.

The flowers are about ¾ long and are borne on to 1 long stalks. They have 5 sepals, 5 petals, 10 stamens, and 1 style. The sepals (calyx) are petal-like, greenish-white, linear, and ¼ to long, shorter and narrower than the petals. They are moderately to densely hairy. The petals are greenish-white, narrowly oblong, and 5 16 to 7 16long. They are densely covered with woolly hairs. The stamens are two alternating series, one long and one short, with hairy filaments and yellow anthers. The style is short.

The fruit is a 3 to 6 long, ¾ to 2 wide, to thick, leathery, more or less oblong, flattened, straight or curved pod with 1 to 7 seeds. The pod is yellowish and velvety-hairy at first, later turning turn brown woody. The fruit ripens in Autumn and remains on the tree through the winter. The seeds are to ¾ long and embedded in a green jelly-like pulp.

 
Similar
Species

 

 
Pests and Diseases

Relatively disease and pest resistant


Distribution Distribution Map  

Sources: 2, 3, 4, 5, 6, 8, 24, 28, 29, 72.

 
Record

The champion Kentucky coffee tree in Minnesota is on city property in Owatonna, in Steele County. In 2009 it was measured at 68 tall and 138 in circumference (44 in diameter).


Comments

Seed Dispersal
The large fruit pods of Kentucky coffee tree are probably an adaptation to large mammals of the Pleistocene epoch. Horses, giant sloths, mastodons, and mammoths were present on the North American continent for millions of years. They probably ate the pods and dispersed the seeds in their scat. They disappeared in the Late Pleistocene extinction event, 20,000 to 10,000 years ago, when all large mammals (over 2,200 pounds) in North America went extinct.


Taxonomy

Family:

Fabaceae (pea)

 

Subfamily:

Caesalpinioideae

 

Tribe:

Caesalpinieae

 
Synonyms

Gymnocladus dioica (FNA – misspelling?)

 
Common
Names

Kentucky coffee tree

Kentucky coffee-tree

Kentucky coffeetree

   

 

 

 

 

 

 

 

 

Glossary

bipinnate

Twice pinnate. Divided into leaflets that are further pinnately divided.

 

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.

 

linear

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

 

perfect

Referring to a flower that has both male and female reproductive organs.

 

pinna

The primary division of a compound leaf or fern frond. Plural: pinnae.

 

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.

 

sucker

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

       

Visitor Photos

   
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Randy


Kentucky coffeetree flower, Freeborn Co., Minn., June 2017

  Kentucky coffee tree   Kentucky coffee tree
       

Old growth Kentucky coffee tree stand, including a long dead fallen giant, west of Faribault, MN, October 2016

  Kentucky coffee tree    
       

Kentucky coffee tree in Owatonna, MN in July 2016

  Kentucky coffee tree   Kentucky coffee tree
       
  Kentucky coffee tree   Kentucky coffee tree
       
  Kentucky coffee tree   Kentucky coffee tree

       
       
       

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  Gymnocladus dioicus
Blake C. Willson
 
  Gymnocladus dioicus  
 
About

Kentucky Coffeetree

 
     
  Gymnocladus dioicus
Angie Holmberg
 
   
 
About

Published on Jul 29, 2014

Description

 
     

 

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  Gymnocladus dioicus
VT Dendrology
 
   
 
About

Published on Apr 12, 2016

Kentucky coffeetree

 
     
  Trees with Don Leopold - Kentucky coffeetree
ESFTV
 
   
 
About

Published on Nov 4, 2011

 
     
  Kentucky Coffee Tree.mov
Kimberly Wade
 
   
 
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Uploaded on Sep 9, 2010

Richard Weber, owner of Springhouse Gardens in Nicholasville, Kenucky, talked about the Kentucky Coffee Tree during the Tree Walk at The Lexington Cemetery. The Lexington Cemetery is home to 200 species of trees.

 
     
  how to identify Gymnocladus dioicus
Laura Deeter
 
   
 
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Uploaded on Oct 2, 2008

short movie on the key id features

 
     
  Great Trees Trail: Kentucky Coffeetree
MortonArboretum
 
   
 
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Published on Oct 9, 2014

Joe Rothleutner, Tree Improvement Specialist, discusses the Kentucky Coffeetree on The Morton Arboretum's Great Trees Trail.

 
     

 

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Visitor Sightings

   
Share your sighting of this plant.

Randy
June, 2017

Location: Freeborn Co., MN

Kentucky coffeetree flower

Kentucky coffee tree


Randy
October, 2016

Location: West of Faribault, MN

Old growth Kentucky coffee tree stand, including a long dead fallen giant

Kentucky coffee tree


Randy
July, 2016

Location: Owatonna, MN

Kentucky coffee tree


Randy
9/22/2015

 

Kentucky coffee tree


     
     
 

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