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■ (SPEC) Iris giganticaerulea Small

1929, Small

Iris giganticaerulea (John Kunkel Small, R. 1929); Vinic; 32-48" (80-120 cm); Color Class-BD; , illustrated in color; Starker 1932; Berkeley 1939; synonym giganticoerulea

See below:
giganta4.jpggiganta5.jpggigantic01.JPGgigantic03.JPGgigantic04.JPGgigantic05.JPGgigantic06.JPGgigantic07.JPGgigantic1.jpggigantic2.jpggigantic3.jpggigantic4.jpggigantic41.jpggiganticaerulea09.jpeggiganticaerulea Addisonia 452.jpggiganticareulea1.jpgigiganticaerulea01.jpg


Addisonia gives:


Big Blue Iris. Native of the Mississippi Delta. Family Iridaceae Iris Family. lris giganticaerulea Small, sp.nov.

While driving along the bayous and canals between New Orleans and Houma, Louisiana, about dusk on April 9th, 1925, a blue iris was several times observed growing on the water's edge. Little attention was paid it, as we were making haste to reach the Rio Grande and western Texas. The iris' flowering season was nearly past, and casual observation suggested that the plant might represent Iris Kimballiae of northern Florida. But closer acquaintance with the plant seen on the trip referred to proved it to be quite different from any previously described species.

Although specifically well isolated, Iris giganticaerulea has taxonomic associates which collectively indicate a common ancestor. This presumably grew in the southeastern highlands during the latest general submergence of the continent, in the Tertiary Period. As the land later became elevated, descendants took different courses, radiating into the Coastal Plain through a sector of about a quarter circle. Thus we now find Iris rivularis in the Atlantic Coastal Plain in Georgia and northeastern Florida; Iris savannarum in the peninsular Florida Coastal Plain; Iris Kimballiae in the East Gulf Coastal Plain ; and Iris giganticaerulea in the Mississippi Delta. If this theory of migration be correct, it is curious to notice that the two descendents that have migrated the greater distance have developed into the most showy plants — with the largest flowers and the largest fruits. As far as we know, this iris left no evidence in the trail it may have followed, however, for at present it is not known outside of the lower part of the Mississippi Delta. In its native habitat it grows mostly in the open and thrives best without any shade. Its rootstocks are usually imbedded in the soil that also supports a turf of grasses and sometimes asters.

The specimen from which the accompanying illustration was made was collected near Morgan City, Louisiana, by Charles A. Mosier and the writer on April 19, 1927. Plants survived the following winter at The New York Botanical Garden and flowered copiously in June, 1928. That this plant and its associated species of the lower Mississippi Delta can withstand the low temperatures of a climate a thousand miles north of their present habitats seems to indicate that they once had a more northern distribution. The type specimen is in the herbarium of The New York Botanical Garden.

The big blue iris has a very stout fleshy branching rootstock. The leaves are erect, mostly four to six together at the base of the flower-stalk, firm. The blades are linear-attenuate, mostly an inch to an inch and a half wide, bright green and more or less glaucescent. The flower-stalk is erect, usually two and a half to four feet tall, rather stout, with usually two or three flower-bearing nodes below the terminal, the internodes rather prominently ridged or angled below the bases of the leaf -like bracts. The involucre is erect, of usually three main bracts, the outer bract narrowly lanceolate-attenuate, exceeding the flower, keeled along the back, with a very narrow pale margin, the inner (second) bract about equalling the base of the perianth with broad translucent scarious margins. The flowers are usually in pairs at the top of the stalk, and single or paired in the axils of the foliaceous bracts below. The primary terminal flower has a narrow-columnar pedicel one and a half to two inches long, nearly terete. The hypanthium covering the ovary is shorter than the pedicel, bluntly six-angled, bright-green, and together with the pedicel tightly enclosed in the involucre. The flower-tube is cylindric-prismatic, somewhat shorter than the ovary, with nine ribs and grooves. The three sepals are remate, three and three-quarters to four and a half inches long. The claw is broad, concave, somewhat narrowed to the base below the middle; without, light-green, several ridged and striate; within, with a yellowish green body and v he ridge prolonged into a yellow crest in the base of the blade and with two or three lateral ridges which run into the yellow blotch in the base of the blade. The blade is broadly oval or orbicular-oval, longer than the claw; without, with a whitish and veined central area and bluish marginal area; within, mainly violet-blue with white streaks and flecks bordering the yellow blotch and more or less distinctly, but faintly flecked with white throughout. The three petals are somewhat shorter than the sepals, broadly spatulate. The claw is narrowly cuneate, involutely folded near the base; without, white or greenish-white at the base, violet-tinged and striate towards the blade; within, more prominently striate with greenish-brown near the base, violet-striate above. The blade is much longer than the claw; without, dull violet- blue and dark-veined; within, bright-violet-blue and dark-veined, entire, sometimes notched at the apex. The style appendages are half-ovate, nearly 2 cm. long, violet, and often whitish near the base without, sharply and irregularly serrate. The stigma is two-lobed, the lobes white-margined. The capsule is drooping, ellipsoid or slightly ovoid-ellipsoid, three to four inches long, bright-green, with six broad rounded ridges, thick-matted. The seeds are numerous, in two rows in each capsule-cavity, nearly a half inch broad, irregularly half-orbicular, sometimes very thick, brown, corky- walled.

John K. Small



Chromosome counts

2n=44, Randolph 1934 ex Randolph & Mitra in Bulletin of the American Iris Society 140, 58: 1956; 2n=44 Riley 1942; 2n=42, R C Foster 1937 (as hex.var. gig. ); 2n=44, Randolph, 1966. ----


Iris giganticaerulea has the following named forms; 'Angel Wings', 'Atrocyanea', 'Barbara Elaine Taylor', 'Bayou Barataria', 'Bayou Boeuf', 'Bayou St John', 'Bette Lee', 'Billy Mac', 'Biloxi', 'Cameron White', 'China Blue', 'Citricristata', 'Citricristata Alba', 'Citriviola', 'Coteau Holmes', 'Creole Can-Can', 'Easter Surprise', 'Elephantina', 'Excitement', 'Florence Zacharie', 'Gentilly Road', 'Gheen's White', 'Giganticaerulea Alba', 'Giganticaerulea Royal', 'Gulf Mist', 'Her Highness', 'High Hat', 'Iberville', 'Isle Bonne', 'Joe Mac', 'Kildea', 'La Bahia ', 'Lafitte', 'La Premiere', 'Laughing Water', 'Lazy Day', 'Longfellow's Gabriel', 'Mandeville', 'Miraculosa', 'Paludicola', 'Ruth Holleyman', 'Silverblu ', 'Snow Flag', 'Snow Goose', 'Southern Accent','Spanish Fort', 'Trixie'. ----


_Iris giganticaerulea crosses;
  • Iris giganticaerulea X LA: 'Amethyst Star'.
  • Iris giganticaerulea X Iris nelsonii: 'Barateria Bay', 'Beau Geste', 'Bonne Idee', 'Coral Bell', 'Eclipse', 'Kisatchie', 'Lafourche'.
  • Iris giganticaerulea X Iris fulva: 'Emma Sample', 'Imosa'.
  • Iris giganticaerulea and Iris fulva: 'Chef Menteur', 'Cherokee', 'Clarette', 'Coweta Creek', 'Imperialis' 'James Zacharie', 'Linda Leach', 'Lockett's', 'Luck', 'Manitou'.
  • Iris fulva X Iris giganticaerulea: 'Lilyana'.
  • LA X Iris giganticaerulea: 'Dora Dey', 'Lillian Bouldin', 'Mary Dunn', 'Katherine L. Cornay', 'Mallard Wing', 'Metairie', 'Miss Louisiana', 'Mistis', 'New Offering', 'Papillon Jaune', 'Pelican State', 'Plaquemine', 'Pointe Ala Hatche', 'Pontchartrain', 'Sunset Richland', 'Rufus', 'Saint Bernard', 'Serene Vitality', 'Sibyl Sample', 'Tiger', 'Tuckahoe', 'Vineyard', 'Vinicolor'.

¼ Iris giganticaerulea crosses: 'Deneb', 'Marsha Sue'. ----

Distribution and Cultivation

Distribution: The distribution of the species gives clues as to its cultural requirements, although plants in cultivation can often tolerate a wider range of variables:
The species is found in the following region:

Bonap's North American Plant Atlas shows the following map reproduced by permission of Kartesz, J.T., The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. ( Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]
Prefers moist soil, but can be grown in good garden soil, well-drained and flourishes in full sun to part shade. Copius water during bloomseason. See Cultivation of Louisiana Irises
See more about preservation of Iris Giganticaerulea at Louisiana Iris Preservation Project

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-- Main.RPries - 2010-01-12
I Attachment Action Size Date Who Comment
giganta4.jpgjpg giganta4.jpg manage 201 K 07 Jul 2020 - 01:59 UnknownUser Photo by Cindy Dufrene-Cindy's Louisiana Iris
giganta5.jpgjpg giganta5.jpg manage 203 K 07 Jul 2020 - 01:59 UnknownUser Photo by Cindy Dufrene-Cindy's Louisiana Iris
gigantic01.JPGJPG gigantic01.JPG manage 107 K 29 Apr 2014 - 15:33 UnknownUser Photo by Benny Trahan
gigantic03.JPGJPG gigantic03.JPG manage 57 K 29 Apr 2014 - 15:42 UnknownUser Photo by Benny Trahan
gigantic04.JPGJPG gigantic04.JPG manage 62 K 29 Apr 2014 - 15:44 UnknownUser Photo by Benny Trahan
gigantic05.JPGJPG gigantic05.JPG manage 70 K 29 Apr 2014 - 15:46 UnknownUser Photo by Benny Trahan
gigantic06.JPGJPG gigantic06.JPG manage 83 K 25 Jan 2016 - 12:56 UnknownUser Photo by Benny Trahan
gigantic07.JPGJPG gigantic07.JPG manage 63 K 25 Jan 2016 - 12:57 UnknownUser Photo by Benny Trahan
gigantic1.jpgjpg gigantic1.jpg manage 161 K 26 Mar 2018 - 13:41 UnknownUser Photo by Cindy Dufrene- Cindy's Louisiana Iris
gigantic2.jpgjpg gigantic2.jpg manage 181 K 26 Mar 2018 - 13:41 UnknownUser Photo by Cindy Dufrene- Cindy's Louisiana Iris
gigantic3.jpgjpg gigantic3.jpg manage 247 K 09 Apr 2018 - 02:50 UnknownUser Photo by Cindy Dufrene- Cindy's Louisiana Iris
gigantic4.jpgjpg gigantic4.jpg manage 150 K 06 Apr 2021 - 21:41 UnknownUser Photo by Diane Louw -Cindy's Louisiana Iris
gigantic41.jpgjpg gigantic41.jpg manage 38 K 06 Apr 2021 - 21:41 UnknownUser Photo by Cindy Dufrene-Cindy's Louisiana Iris
giganticaerulea09.jpegjpeg giganticaerulea09.jpeg manage 56 K 18 Feb 2020 - 20:33 UnknownUser Photo scanned from the Carla Lankow slide collection
giganticaerulea_Addisonia_452.jpgjpg giganticaerulea_Addisonia_452.jpg manage 50 K 08 Nov 2013 - 14:26 BobPries Biodiversity Heritage Library
giganticareulea1.jpgjpg giganticareulea1.jpg manage 54 K 26 Jun 2016 - 02:39 UnknownUser Photo by Joe Musacchia
igiganticaerulea01.jpgjpg igiganticaerulea01.jpg manage 63 K 19 Aug 2014 - 21:47 UnknownUser Photo by Iris City Gardens
Topic revision: r18 - 04 Apr 2022, TLaurin
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