plains prickly pear

(Opuntia macrorhiza)

Conservation Status

IUCN Red List

LC - Least Concern

NatureServe

N5 - Secure

S3 - Vulnerable

Minnesota

Special Concern

 
plains prickly pear
 
Description

Plains prickly pear 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 16 to 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.

 

Height

3 to 6¼

 

Flower Color

Yellow

 

Similar Species

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

Habitat

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

Ecology

Flowering

Mid-June to July

 

Pests and Diseases

 

Use

 

Distribution

Distribution Map

 

Sources

2, 3, 4, 5, 6, 7, 24, 28, 29, 30.

5/24/2025    
     

Nativity

Native

     

Occurrence

Common

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) / Angiospermae (flowering plants)

Class

Magnoliopsida (flowering plants)

Subclass

Caryophyllidae

Superorder

Caryophyllanae

Order

Caryophyllales (pinks, cactuses, and allies)

Family

Cactaceae (cactus)

Subfamily

Opuntioideae

Tribe

Opuntieae

Genus

Opuntia (prickly pears)

   

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 Minnesota Biodiversity Atlas reports 37 collected specimens as O. humifusa and only 2 as O. macrorhiza. Some authorities use the Minnesota Biodiversity Atlas as one of their sources or their only source of species distribution in the state. BONAP shows only O. humifusa in the state. USDA PLANTS shows both species occurring in the state with almost identical distributions. The Minnesota DNR acknowledges the confusion and uses the name O. macrorhiza for all occurrences in the state.

According to Flora of North America, 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 flowers with red at the base of the inner tepals. If the FNA descriptions are correct, then the correct name for prickly pears in Minnesota with large, pad-like segments is O. macrorhiza.

   

Subordinate Taxa

 

   

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

On plants: Part of the pistil, usually a slender stalk, connecting the ovary to the stigma(s). On flies (Diptera): A terminal, often slender or pointed, appendage arising from the end of the last, usually third, antennal segment.

 

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.

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Verónica Aponte

Pricky Pear in Minneapolis

It is in the sidewalk flower patch in front of my house

plains prickly pear   plains prickly pear
     
plains prickly pear   plains prickly pear
     
plains prickly pear    
MinnesotaSeasons.com Photos
plains prickly pear   plains prickly pear

Plant

 

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Inflorescence

     
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Young pad

 

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Mature pad

 

 

 

 

 

 

Spines

     
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Fruiting plant

 

Infructescence

     
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  plains prickly pear
 

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Infructescence

 

 

 

Camera

Slideshows

Opuntia humifusa
Joshua Mayer

Opuntia humifusa
About

Eastern Prickly Pear Cactus

 

slideshow

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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

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Verónica Aponte
5/24/2025

Location: Minneapolis, MN 55412

It is in the sidewalk flower patch in front of my house

plains prickly pear
MinnesotaSeasons.com Sightings

 

 

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Created: 9/7/2005

Last Updated:

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