plains prickly pear

(Opuntia macrorhiza)

               
Conservation Status

IUCN Red List

LC - Least Concern

plains prickly pear

NatureServe

N5 - Secure

S3 - Vulnerable

Minnesota

Special Concern

Nativity

Native

Occurrence

Common

Habitat

Dry. Prairies, dunes, lakeshores. Rocky or sandy soil. Full sun.

Flowering

Mid-June to July

     
Flower Color

Yellow

     
Height

3 to 6¼

     

Identification

This is a low, succulent, spiny, perennial shrub that rises from tuberous, somewhat woody roots. It usually forms a 3 to 6¼ high mound but may also form a 24 to 60 in diameter mat.

The stems are prostrate or spreading, branched, and often divided into 2 or 3 segments (pads). The pads are not easily detached. If broken apart, the separated segment can send down new roots and form a new plant.

Each pad is greatly flattened, egg-shaped to circular, 2¾ to 4¼ long, and 1 to 3 wide. It is dark green, dull, and hairless. It is covered with a thick, waxy skin. It is usually fleshy and usually smooth but may become flabby and wrinkled with the approach of winter or when stressed.

On the surface of each pad are a number of woolly patches (areoles). Areoles are actually extremely short modified branches. They are widely spaced, mostly to 1¼ apart, and are arranged in diagonal rows. The row at the widest part of the pad has usually 5 or 6, sometimes 7 or 8, areoles.

Each areole is oval to circular and 1 16 to in diameter. It is covered with a dense tuft of numerous 1 16to 3 16 long barbed hairs (glochids). The glochids are pale yellowish-brown or tan at first, becoming brown as they age. They have minute downward-pointing barbs and are easily detached. All areoles usually also have 1 to 4 true spines. Spines are denser toward and on on the margins of the pad. The spines are white to reddish-brown, straight, needle-shaped, stout at the base, erect to spreading, and to 2¼ long. They are round or only slightly flattened on cross section. They are not easily detached.

The inflorescence is 1 to several flowers rising singly from areoles on the margin of the pad. The flowers are broadly funnel-shaped, 2 to 3 in diameter, and showy. There are 3 petals, 3 petal-like sepals (6 tepals), numerous stamens, and 1 style. The tepals are tepals are 1 to 1½ long, the outer tepals shorter than the inner. The outer tepals are egg-shaped and green at the base grading to yellow at the margins. The inner tepals are inversely egg-shaped to spoon-shaped and have an abrupt, short, sharp point at the tip. They are mostly yellow but usually tinged with orange or red at the base. The stamens have long slender filaments and small yellow anthers. The style is stout and has 4 to 9 stigma lobes.

The fruit is an elongated, inversely egg-shaped, 1 to 1½ long, to 1 in diameter berry with numerous seeds. It is fleshy, juicy, hairless, and green at first, becoming dull red or purple when ripe. The fruit has glochids, sometimes restricted to the upper margin, but no spines. It matures from mid-July to mid-September. It is edible.

 
Similar
Species

Brittle prickly pear (Opuntia fragilis) stems are only slightly flattened. They do not look like pads.


Distribution Distribution Map  

Sources: 2, 3, 4, 5, 7, 28.


Comments

Taxonomic Uncertainty
According to the Minnesota DNR’s Rare Species Guide there is disagreement as to which species of Opuntia, O. humifusa or O. macrorhiza, occurs in Minnesota, but there is agreement that only one does. The Bell Herbarium4 at the University of Minnesota reports all collected specimens as eastern prickly pear (O. humifusa). Some authorities use the Bell Herbarium as one of their sources or their only source of species distribution in the state. BONAP2 shows only O. humifusa in the state. PLANTS3 shows both species occurring in the state with similar distributions. The DNR6 shows only O. macrorhiza occurring in the state.

According to FNA45, O. macrorhiza inner tepals are red at the base while those of O. humifusa are yellow throughout. The photos on the DNR’s Rare Species Guide, and photos on MinnesotaSeasons.com, show a flowers with red at the base of the inner tepals, making them clearly O. macrorhiza.


Taxonomy

Family:

Cactaceae (cactus)

 

Subfamily:

Opuntioideae

 

Tribe:

Opuntieae

 
Synonyms

Opuntia grandiflora

Opuntia macrorhiza var. macrorhiza

Opuntia leptocarpa

Opuntia mackensenii

Opuntia plumbea

Opuntia sphaerocarpa

Opuntia compressa var. grandiflora

Opuntia compressa var. macrorhiza

Opuntia compressa var. stenochila

 
Common
Names

grassland pricklypear

plains prickly pear

plains prickly-pear

plains twistspine pricklypear

tuberous prickly pear

twist-spine prickly-pear

twistspine pricklypear

western prickly pear


 

 

 

 

 

 

 

Glossary

areole

A well-defined, woolly, hairy, or cushion-like structure, unique to cacti, from which spines, glochids, branches, and flowers originate.

 

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.

 

glochid

A small, barbed or hooked hair or bristle on a cactus.

 

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 Odonata and Hymenoptera, a blood-filled blister or dark spot at the leading edge of each wing toward the tip, thought to dampen wing vibrations and signal mates. In Lepidoptera, an area of specialized scent scales on the forewing of some skippers, hairstreaks, and moths.

 

style

Part of the pistil, usually a slender stalk, connecting the ovary to the stigma(s).

 

tepal

Refers to both the petals and the sepals of a flower when they are similar in appearance and difficult to tell apart. Tepals are common in lilies and tulips.

       

Visitor Photos

   
Share your photo of this plant.

       
       
       
       

MinnesotaSeasons.com Photos

   

Plant

  plains prickly pear   plains prickly pear
       

Flowering Plant

  plains prickly pear   plains prickly pear
       
  plains prickly pear    
       

Fruiting Plant

  plains prickly pear   plains prickly pear
       

Inflorescence

  plains prickly pear    
       

Flower

  plains prickly pear   plains prickly pear
       

Young Pad

  plains prickly pear   plains prickly pear
       

Mature Pad

  plains prickly pear    
       

Infructescence

  plains prickly pear   plains prickly pear
       

Fruit

  plains prickly pear    
       

Spines

  plains prickly pear    
       
       

 

Camera

     

Slideshows

   
  Eastern Prickly Pear (Opuntia humifusa)
Bill Keim
 
  Eastern Prickly Pear (Opuntia humifusa)  
     
  Opuntia humifusa
Joshua Mayer
 
  Opuntia humifusa  
 
About

Eastern Prickly Pear Cactus

 
     

 

slideshow

     

Visitor Videos

   
Share your video of this plant.

     
     

Other Videos

 
  Opuntia Macrorhiza in Oklahoma
Kyle K
 
   
 
About

Uploaded on Nov 6, 2009

A video of Opuntia Macrorhiza and its habitat I filmed whilst visiting Oklahoma in October 2009.

List of noticed companion plants:
Mullein
Various tall grasses
Yucca

 
     

 

Camcorder

         

Visitor Sightings

   
Share your sighting of this plant.

     
     
 

MinnesotaSeasons.com Sightings

   


 

 

Binoculars

Last Updated:

About Us | Privacy Policy | Contact Us | © 2017 MinnesotaSeasons.com. All rights reserved.