southern blue flag

(Iris virginica var. shrevei)

Conservation Status

IUCN Red List

not listed

NatureServe

N5 - Secure

SNR - Unranked

Minnesota

not listed

Wetland Indicator Status

Great Plains

OBL - Obligate wetland

Midwest

OBL - Obligate wetland

Northcentral & Northeast

OBL - Obligate wetland

 
southern blue flag
 
 
Description

Southern blue flag is a 20 to 40 tall, erect, perennial forb that rises on a single stem from a thick, creeping, freely-branching rhizome and fleshy roots. It often forms dense clumps.

The stems are erect to arching and usually have 2 or 3 branches. They seldom fall over after flowering. They are shorter than the leaves so that the leaves rise above the flowers.

Basal leaves are narrowly sword-shaped, green to grayish-green, 23½ to 31½ long, and 1 to 13 16 wide. They are erect and commonly arching near the top. There are 1 or 2 leaves on the stem subtending each branch. Stem leaves are similar to the basal leaves but shorter.

The inflorescence is 2 or 3 flowers at the end of the stem and 1 or 2 flowers at the end of the branch. The cluster emerges from an enveloping pair of large bracts (spathes).

The flowers are 3 to 3½ wide. There are 3 petals and 3 petal-like sepals, all of which are fused at the base into a to ¾ long tube. Each sepal is egg-shaped to oval, widely spreading, arched, 1½ to 2¾ long, and ¾ to 1½ wide. It is abruptly or gradually narrowed toward the base (clawed) and broadly expanded toward the tip. It is pale blue to purple near the tip quickly fading to white with darker blue or purple veins toward the middle. There is a bright yellow patch near the throat. The claw is green in the center, surrounded by bright yellow, with purple veins. What appears to be an upper lip is actually a branch of the style. The highly modified style is enlarged and divided into 3 branches. Each petal-like style branch covers the lower portion of a one sepal, extending just beyond the narrowed claw and concealing the stamens. The style branch is 13 16 to 1 long, distinctly ridged, and flared at the tip. It does not have ear-like lobes at the base. The 3 petals are smaller than the sepals. They are lance-shaped to spatula-shaped, erect, 1¼ to 2¾ long, and to 1¼ wide. They are often notched at the tip. The flowers last 1 to 4 days and are somewhat fragrant. All white flowers are found, though rarely.

The fruit is a green, elliptical to egg-shaped, three-sided, 1¼ to 2 long, to ¾ in diameter capsule. It is rounded-triangular in cross section.

 

Height

20 to 40

 

Flower Color

Lavender to violet

 

Similar Species

Northern blue flag (Iris versicolor) top of the stem is equal to or higher than the leaves. The sepals and petals are darker in color, violet blue. The patch at the base of the sepals is yellowish-green, not bright yellow. The 3 petals are not notched at the tip.

Habitat

Wet. Meadows, swamps, marshes, and streambanks. In water less than 40 deep. Full to partial sun.

Ecology

Flowering

May to July

 

Pests and Diseases

 

Use

 

Distribution

Distribution Map

 

Sources

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

5/20/2023    
     

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)

Class

Liliopsida (monocots)

Order

Asparagales (agaves, orchids, irises, and allies)

Family

Iridaceae (irises and allies)

Subfamily

Iridoideae

Tribe

Irideae

Genus

Iris (irises)

Subgenus

Limniris

Section

Limniris

Series

Laevigatae

Species

southern blue flag (Iris virginica)

   

Subordinate Taxa

 

   

Synonyms

Iris shrevei

Iris versicolor var. blandescens

Iris versicolor var. shrevei

   

Common Names

Shreve’s iris

southern blue flag

southern blueflag

Virginia blue flag

 

 

 

 

 

 

 

 

 

Glossary

Bract

Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.

 

Claw

A stalk-like narrowed base of some petals and sepals.

 

Linear

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

 

Rhizome

A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

 

Sepal

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

 

Spathe

One or two large bracts that subtend, hood, or sometimes envelope a flower or flower cluster, as with a Jack-in-the-Pulpit.

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Kirk Nelson

southern blue flag   southern blue flag
     

Southern blue flag iris, on the shore of Pickerel Lake

southern blue flag   southern blue flag
     

Found on the shore of Pickerel Lake

southern blue flag   southern blue flag
MinnesotaSeasons.com Photos

Plant

  Inflorescence
southern blue flag   southern blue flag
     

Flower

southern blue flag   southern blue flag
     
southern blue flag   southern blue flag

 

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Other Videos

blue flag (Iris virginica)
UFInvasivePlantsEDU

About

Uploaded on May 19, 2010

Aquatic and Invasive Plant Identification Series by the UF/IFAS Center for Aquatic and Invasive Plants ( http://plants.ifas.ufl.edu ) and the Florida Fish and Wildlife Commission, Invasive Plant Management Section.

For more information about blue flag, go to http://plants.ifas.ufl.edu/node/206

Video editor/videographer - Phil Chiocchio

Southern Blue Flag Iris
natvikdesign

About

Published on Jun 28, 2012

Wild Iris (Iris virginica) in wetland restoration near Ridgetown, Ontario

 

Camcorder

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Kirk Nelson
5/31/2019

Location: Mississippi National River and Recreation Area - Coldwater Spring

southern blue flag
Kirk Nelson
6/2/2017

Location: Lilydale Regional Park

Southern blue flag iris, on the shore of Pickerel Lake

southern blue flag
Kirk Nelson
6/13/2014

Location: Lilydale Regional Park

Found on the shore of Pickerel Lake

southern blue flag
MinnesotaSeasons.com Sightings

 

 

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