Iris lacustris (Dwarf Lake Iris)

Overview

Threatened

Common Names

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Common Names in English:

Dwarf Lake Iris

Description

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Family Iridaceae

Herbs perennial (or shrubs or annuals ), with rhizomes, bulbs, or corms. Leaves alternate, often 2-ranked, often oriented edgewise to aerial stem, usually sword-shaped to linear , parallel veined, base sheathing . Inflorescence sometimes a spike or reduced to a solitary flower, more often of monochasial , umbellate cymes, each enclosed in 2 opposed bracts (spathes ) and termed a rhipidium, which may be solitary and terminal or numerous and variously arranged in racemes or panicles; bracts 1 to several. Flowers bisexual , showy, usually actinomorphic (often zygomorphic elsewhere) . Perianth segments 6, in 2 whorls, inner and outer ones equal or differing in size and/or color; tube filiform or trumpet-shaped. Stamens (2 or) 3; anthers extrorse . Ovary inferior (or superior), 3-loculed; ovules few to many; placentation axile . Style with filiform, slender, or petaloid branches. Fruit a loculicidal capsule. Seeds with or without aril and wings.

Between 70 and 80 genera and ca. 1800 species: nearly worldwide, especially S Africa, Asia, and Europe; three genera and 61 species (21 endemic, one introduced ) in China.[1]

Genus Iris

Herbs, perennial , from rhizomes [bulbs or fascicles of fleshy roots ]; rhizomes homogeneous with branches like primary in size and texture , or heterogeneous , branches cordlike with scalelike leaves, enlarging at apex to produce vegetative leaves, additional cordlike branches, and flowering stems. Flowering stems simple or branched, erect (declining or semierect and obviously zigzag in I. brevicaulis and some of its hybrids), solid or hollow, terete or slightly flattened. Leaves: basal 3-10, in fan; blade monofacial (except at base ), smooth or ridged , sometimes centrally thickened, veins obscure to prominent ; cauline 0-4 on branched stems, usually similar to basal, subtending each branch , decreasing in length distally, sometimes bracteiform and sheathing stem. Inflorescences rhipidiate, units 1 or more-flowered, spathaceous ; spathes 2, herbaceous with scarious tips , or completely scarious, with or without distinct keel, often persisting and enclosing capsule(s) at maturity. Flowers lasting 1-4 days, upward-facing, usually somewhat fragrant (odor extremely unpleasant in I. foetidissima), pedicellate or sessile; perianth epigynous , white, yellow, tan, brown, copper-red, maroon, blue, blue-violet, or purple, often with markings of contrasting colors, differentiated into sepals and petals, actinomorphic , 4-18 cm diam.; floral tube distal to ovary, terete or occasionally ridged, solid proximally, hollow distally; sepals 3, spreading or reflexed , expanding either gradually or abruptly from claw into broader limb, with signal of prominent ridge, crest , distinct lines or dots, pubescence , or band of multicellular hairs (beard ) along midline of claw and for short distance along midrib of limb; petals 3, erect, spreading or rarely reflexed, sometimes very reduced and mostly hidden by sepal bases; stamens opposite sepals, free but appressed to style branches; style dividing distally into petaloid branches, these arching outward and over stamens and claws of sepals, dividing at apex into 2 rounded or triangular lobes (style crests) ; stigma a lip of tissue on adaxial surface of style arm at base of crest; ovary terete or roundly 3- or 6-angled or -grooved. Fruits capsular , wall papery or becoming dry and hardened, sometimes indehiscent (in I. giganticaerulea) . Seeds 4-20, in 1-2 rows per locule, often flattened in contact with others, rounded on outer surface; seed coat tan to dark brown (red in I. foetidissima), thin, membranous, and smooth, or conspicuously roughened to extensively corky (usually in wetland species), with or without obvious aril. x = uncertain.

Species ca. 280: Northern Hemisphere.

Because irises have large, handsome flowers, have many different forms, colors, and color patterns , and are easily grown and propagated, they have become popular garden ornamentals . Many non-native irises may be found in the flora area, not only in specialized gardens, but in casual plantings and persisting around old dwellings, in cemeteries, and along roadsides. These include not only the more common bearded irises, but members of the Sibirian, Spuria, Japanese, and Dutch groups. In the Pacific Coast and southeastern areas of the flora, repeated hybridization, both natural and artificial, of some of the local species has produced hundreds of garden forms that have added greatly to the popularity of this genus. Asexual reproduction in many Iris species may be more important than sexual reproduction in their persistence , and many hybrid clones may persist for decades in sites no longer cultivated.

The species of Iris differ from members of other native genera of the Iridaceae in North America in three ways: 1) the sets of outer and inner perianth members (sepals and petals herein) differ from each other in shape , orientation, and, in some cases, coloration ; 2) the parts of the flowers��petals, sepals, stamens, and styles��are united basally into a floral tube that surmounts the ovary; and 3) the styles are petaloid and modified with some specialized structures to insure cross pollination .

T. Holm (1929) restricted the term rhizome to a horizontal, usually subterranean , stem that produces roots from its lower surface and green leaves from its apex, developed directly from the plumule of the embryo. He recognized stolons as axillary , subterranean branches that do not bear green leaves but only membranaceous , scalelike ones. The rhizomes of Iris are of two basic kinds: homogeneous, with the branches like the primary one in size and texture, and heterogeneous, with the branches of the primary rhizome like stolons with scalelike leaves. These enlarge at the apex to produce green leaves and more stolonlike branches.

According to B . Mathew (1990), Iris includes six subgenera . Species of subgenera Iris and Limniris are rhizomatous ; the others are either bulbous or perennial from a fascicle of fleshy roots. Three species of subg. Iris are sometimes found naturalized from cultivation in the flora area. Other species of the subgenus are found here only in cultivation or as waifs . The native North American species of Iris all belong to subg. Limniris, usually referred to as the beardless irises. The four other subgenera, which are found in the flora area only in cultivation or as waifs, have all been recognized sometimes as separate genera: subg. Nepalensis (Dykes ) Lawrence as Junopsis Schulze; subg. Xiphium (Miller) Spach as Xiphion Miller; subg. Scorpiris Spach as Juno Trattinnick; and subg. Hermodactyloides Spach as Iridodictyum Rodionenko. F. Köhlein (1987) accepted these four segregate genera; however, most current authors circumscribe Iris in the broad sense, as here.

Elevation is unimportant in the taxonomy and ecology of Iris, and very rarely is it recorded on specimen labels. Consequently, elevations are not reported in the species treatments that follow.[2]

Physical Description

Species Iris lacustris

Rhizomes with proximal cordlike portion 0.8-2 dm × 2 mm, bearing brown, scalelike leaves and rarely roots , distal portion enlarging to 3-5 × 0.8-1.2 cm, producing fibrous roots , 2-3 brown, sheathing , bractlike leaves, then 8-12 green foliage leaves; usually 2 cordlike rhizomes produced from apex as new growth begins in spring . Stems simple , 0.8-4 cm. Leaves: basal with blade broadly linear at anthesis , slightly falcate , 4-6 cm × 6-8 mm, enlarging to 16 cm × 10 mm; cauline with proximal 1-2 resembling basal leaves , 4-6 cm, distal 2 more sheathing of stem, exceeding spathes . Inflorescence units 1(-2) -flowered; spathes green, outer closely sheathing inner and enclosing ovary, slightly keeled at midrib , 4.5 cm, ± equal, margins scarious . Flowers: perianth sky blue; floral tube dull yellow, funnelform , 1-2 cm, dilated upward to 4-5 mm diam.; sepals 2-2.3 × 0.8 cm, tapering gradually into claw , apex emarginate , signal white with deep violet margin, with 3 yellow and white, toothed , low ridges ; petals spreading , narrowly oblanceolate , 1-1.5 × 0.4-0.5 cm, shorter and narrower than sepals, apex emarginate; ovary sharply trigonal , 0.8-1 cm; style 1-2 cm, crests linear to semiovate, 4 mm, margins crenate ; stigmas rounded , margins entire; pedicel 0.6-1.5 cm. Capsules roundly triangular, 1.2 × 8 mm, enclosed in spathes. Seeds dark brown, with white appendage spiraled around seed, ca. 3 mm, quickly drying when exposed to air . 2n = 32, 42. [source]

Several authors have described Iris lacustris simply as being very similar to I. cristata, but smaller in every detail. W. R. Dykes (1913) said, �This name may be retained as that of a local form or variety but it hardly deserves specific rank.� He treated the taxon as I. cristata var. lacustris. R. C. Foster (1937) discussed the relationship between I. cristata and I. lacustris in detail, and recognized the latter at specific rank. He stated, �It is interesting to note that it has been recorded in several localities on or near the Bruce Peninsula, Ontario, that home of so many pre-Wisconsin relics . Professor Fernald informs me that he has seen it growing there in some abundance on the upper levels of the sandy beaches. Quite probably, it is present there, not as a newcomer, but as a relic.� However, G. L. Hannan and M. W. Orick (2000) concluded that I. lacustris is a product of some post-glacial invasion or introduction of a plant or seed of I. cristata that has developed its own very stable and quite unvariable character. [source]

Habit: Forb/herb

Flowers: Bloom Period: May. • Flower Color: blue-violet, lavender, purple, violet

Size/Age/Growth

Size: under 6" tall.

Habitat

Moist, sandy gravel , limestone shores of lakes [3].

Biology

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Reproduction

Duration: Perennial

Growth

Sunlight: Sun Exposure: Full sun to partial shade.

Temperature: Cold Hardiness: 5a, 5b. (map)

Taxonomy

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Domain: Eukaryota () - Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Plantae () - Haeckel, 1866 - Plants
  - Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
    - Phylum: Tracheophyta () - Sinnott, 1935 Ex Cavalier-Smith, 1998 - Vascular Plants
      - Subphylum: Euphyllophytina ()
        Infraphylum: Radiatopses () - Kenrick & Crane, 1997
        Class: Liliopsida () - Scopoli, 1760
        Subclass: Liliidae () - Takhtajan, 1967
        Superorder: Lilianae () - Takhtajan, 1967
        Order: Iridales () - Dumortier, 1829
        Family: Iridaceae () - A.l. De Jussieu, 1789 - Iris Family
        Subfamily: Iridoideae ()
        Tribe: Irideae ()
        Genus: Iris () - Linnaeus, Sp. Pl. 1: 38. 1753; Gen. Pl. ed. 5, 24. 1754.
        Specific epithet: lacustris - Nuttall, Gen. N. Amer. Pl. 1: 23. 1818.
        Botanical name: - Iris lacustris

Unambiguous Synonyms

Coscinodiscus lacustris iris /i> (Hribaud & Brun) Playfair
Coscinodiscus lacustris iris (Hã©ribaud & Brun) Playfair
Iris cristata lacustris (Nutt.) Iltis
Iris cristata Solander ex Aiton lacustris (Nuttall) H. H. Iltis
Iris cristata var. lacustris (Nutt.) Dykes
Iris cristata var. lacustris (Nuttall) Dykes

Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 15-Mar-2000

Place of publication : Gen. N. Amer. pl. 1:23. 1818

Name verified on 15-Apr-1994 by ARS Systematic Botanists. Last updated: 03-Dec-2004

Similar Species

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Members of the genus Iris

ZipcodeZoo has pages for 20983 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

More Info

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Notes

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Contributors

Bisby, F.A., Y.R. Roskov, M.A. Ruggiero, T.M. Orrell, L.E. Paglinawan, P.W. Brewer, N. Bailly, J. van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Species 2000: Reading, U.K.
Global Biodiversity Information Facility. Accessed November 25, 2007. http://www.gbif.org Mediated distribution data from 3 providers.
"Iris lacustris". in Flora of North America Vol. 26 Page 373, 378. Published by Oxford University Press. Online at EFloras.org.
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (April 28, 2008)

Data Sources

Accessed through GBIF Data Portal November 25, 2007:

Canadian Museum of Nature, Canadian Museum of Nature Herbarium
USDA PLANTS, USDA PLANTS Database

Identifiers

Biodiversity Heritage Library NamebankID: 3926165
Catalogue of Life Accepted Name Code: ITS-43218
Global Biodiversity Information Facility Taxonkey: 13755799
Globally Unique Identifier: urn:lsid:ipni.org:names:438775-1
GRIN Nomen Number: 320043
Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 43218
International Plant Names Index (IPNI) ID: 130094-2
Natural Heritage Network Species Identifier: PMIRI090H0
U.S. Fish and Wildlife Service Species Identifier: Q2BS
U.S.D.A. Plant Symbol: IRCRL2
Zipcode Zoo Species Identifier: 44365

Footnotes

Yu-tang Zhao, Henry J. Noltie & Brian F. Mathew "Iridaceae". in Flora of China Vol. 24 Page 297. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
http://bugguide.net/index.php?q=search&keys=Iris&search=Search [back]
"Iris lacustris". in Flora of North America Vol. 26 Page 373, 378. Oxford University Press. Online at EFloras.org. [back]

Iris lacustris

Overview

Common Names

Description

Family Iridaceae

Genus Iris

Physical Description

Species Iris lacustris

Size/Age/Growth

Habitat

Biology

Reproduction

Growth

Taxonomy

Unambiguous Synonyms

Notes

Similar Species

Members of the genus Iris

More Info

Further Reading

Notes

Contributors

Data Sources

Identifiers

Footnotes