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iris de virginie, southern blue flag, Virginia iris

prairie iris, savanna iris

Rhizomes

many-branched, forming dense clumps, 2–4 cm diam., usually covered with remnants of old leaves;

roots fleshy.

greenish, freely branching, forming large, open clumps, 2–2.5 cm diam., fleshy, with fibrous bases of old leaves not covering rhizome but persisting on ringlike scars.

Stems

rather weak, often falling over after flowering, solid, usually 1-branched, 5–10 dm.

1-branched, solid, 3–10 dm.

Leaves

basal erect or often flexible, blade gray-green to bright green, buff to purplish basally, with several prominent ribs in mature leaves, linear-ensiform, 6–8 dm × 2.5–3 cm, apex acute.

basal usually dying back shortly after anthesis, blade bright green, 6–10 dm × 0.8–2 cm, sometimes glaucescent;

cauline with blade elongate, linear-attenuate, 15–20 cm, exceeding flowers.

Inflorescence units

2–3-flowered, branch units 1–2-flowered;

spathes compact, often with brown striations, ridged, unequal, outer 3–8 cm, inner 8–14 cm, firm, herbaceous.

1–3-flowered, branch units 1–2-flowered;

spathes lanceolate, subequal or unequal, apex acute;

outer 8–10 cm, herbaceous, margins scarious;

inner 6–9 cm, completely scarious.

Flowers

perianth lavender to violet, rarely white;

floral tube constricted above ovary, 1–2 cm;

sepals spreading and arched, pale blue to purple with darker blue or purple lines, obovate to oval, 4–8.4 × 1.6–4 cm, base abruptly attenuate, claw green in median, bordered by yellow ground with blue or purple lines, yellow extending onto base of limb as finely pubescent signal patch;

petals oblong-lanceolate to oblong-spatulate, 3–7 × 1–3 cm, claw greenish yellow with blue or purplish lines, apex often emarginate;

ovary trigonal, 1.3–3.8 cm;

style inwardly auriculate at convergences, 3–4.5 cm, crests reflexed, 0.7–2 cm;

stigmas unlobed, with prominent triangular tongues, margins entire;

pedicel 2.5–8 cm.

perianth blue to blue-violet (white in forma albispiritis);

floral tube funnelform, 1.2–1.5 cm;

sepals blue or pale violet with flecks of white and lines of deeper blue on either side of ridge, spatulate, elliptic to ovate, 7–8 cm, apex acuminate, ridge yellow, linear, extending to about middle of limb, finely pubescent, claw light green, striated, ribbed, 1–1.2 cm;

petals erect or spreading-erect, deep blue, linear to narrowly linear-spatulate, 6–7.5 cm, base abruptly attenuate into claw, claw channeled, green with darker lines, margins pale;

ovary bluntly 3-angled, ridged at each angle and on faces between angles;

style linear-acute, 5–6 cm;

crests ovate, 1–2 cm, margins sharply and irregularly toothed;

stigmas broadly 2-lobed, margins crenate;

pedicel 1.6–2 cm.

Capsules

ovoid, ellipsoid, or long-cylindric, trigonal or polygonal in cross section, 3–6 × 1–2 cm.

ellipsoid, round in cross section, roundly 6-lobed, with 6 sharp, winglike, equally spaced ridges converging to form stout beak at apex, 6–10 cm, dehiscence loculicidal.

Seeds

in 2 rows per locule, pale brown, usually D-shaped, 5–8 mm, pitted, corky.

in 1 row per locule, brown, circular or uneven, flattened, 8–12 mm diam, very corky.

2n

= 70, 72.

= 44.

Iris virginica

Iris savannarum

Phenology Flowering May–Jun. Flowering late Mar–early Apr.
Habitat Wetlands, margins of lakes and streams Wet ditches, margins of lakes, streams, and swamps
Distribution
from FNA
AL; AR; DC; FL; GA; IA; IL; IN; KS; KY; LA; MD; MI; MN; MO; MS; NC; NE; NY; OH; OK; PA; SC; TN; TX; VA; WI; WV; ON; QC
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from FNA
AL; FL; GA
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Discussion

Plants of Iris virginica from the southeastern and south-central states having stems 2–3-branched and seldom falling to the ground after flowering, and with capsules long-cylindric have been recognized as var. shrevei.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Iris savannarum has often been included in I. hexagona, but differs in several ways. The capsules of I. hexagona are more obviously hexagonal, with smooth faces alternating with those that have two rounded lobes, whereas the capsules of I. savannarum are more rounded but with six obvious ridges, almost of winglike proportions. Iris hexagona has yellow-green leaves instead of the brighter green of I. savannarum. The leaves of I. savannarum die back after anthesis, while those of I. hexagona remain green. The flowering period of I. savannarum is almost one month earlier than that of I. hexagona in the area where both are known to grow. The sepals of I. savannarum are more acute at the apex than those of I. hexagona.

Iris savannarum has been hybridized with Iris fulva to produce I. ×cacique (J. Berry) N. C. Henderson.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 26, p. 390. FNA vol. 26, p. 393.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Laevigatae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae
Sibling taxa
I. bracteata, I. brevicaulis, I. chrysophylla, I. cristata, I. douglasiana, I. fernaldii, I. fulva, I. germanica, I. giganticaerulea, I. hartwegii, I. hexagona, I. hookeri, I. innominata, I. lacustris, I. longipetala, I. macrosiphon, I. missouriensis, I. munzii, I. orientalis, I. pallida, I. prismatica, I. pseudacorus, I. pumila, I. purdyi, I. savannarum, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor
I. bracteata, I. brevicaulis, I. chrysophylla, I. cristata, I. douglasiana, I. fernaldii, I. fulva, I. germanica, I. giganticaerulea, I. hartwegii, I. hexagona, I. hookeri, I. innominata, I. lacustris, I. longipetala, I. macrosiphon, I. missouriensis, I. munzii, I. orientalis, I. pallida, I. prismatica, I. pseudacorus, I. pumila, I. purdyi, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
Synonyms I. caroliniana, I. georgiana, I. shrevei, I. virginica var. shrevei I. albispiritus, I. hexagona var. savannarum, I. kimballiae, I. rivularis
Name authority Linnaeus: Sp. Pl. 1: 39. (1753) Small: Addisonia 9: 57, plate 317. (1925)
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