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fleur-de-lis, horticultural iris, iris jaune, pale-yellow iris, yellow flag, yellow iris, yellow water iris

slender blue iris

Rhizomes

pink, freely branching, producing extensive clumps, 2–3 cm diam., with fibrous remains of old leaves;

roots fleshy.

superficial or only slightly buried in peaty soil, cordlike portions usually 1-branched, 40 cm × 2–5 mm, bearing scalelike leaves at nodes;

nodal roots absent.

Stems

usually 1-branched, solid, 7–15 dm.

simple or 1–2-branched, 3–8 dm.

Leaves

basal deciduous, at first erect, then recurved, blade dark green, with prominent median thickening, 4–10 dm × 2–3 cm, slightly glaucous basally;

cauline equaling inflorescence unit.

basal with blade slightly ribbed, 3–6 dm × 0.2–0.5 cm;

cauline 1–4, erect.

Inflorescence units

4–12-flowered;

spathes green with brown margins, outer spathe strongly keeled, inner without keel, 6–9 cm, subequal, margins not scarious.

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

spathes pale brown, narrowly lanceolate, 2–4 cm, scarious or partially membranaceous.

Flowers

perianth bright yellow;

floral tube 0.6–0.8 cm, with no constriction into ovary;

sepals bright yellow or cream colored, lanceolate to ovate or suborbiculate, 5–7.5 × 3–4 cm, base abruptly attenuate, claw ca. 1/2 length of limb, signal a darker yellow basal patch limited by short, brown lines;

petals without veining, lanceolate to spatulate, 2–3 cm;

ovary triangular in cross section with concave sides and narrow groove at each angle, 1.5 cm;

style keeled, 3–4 cm, crests spreading, 1–1.2 cm, laciniate at apex;

stigmas rounded with prominent tongue;

pedicel 2.5–7 cm.

perianth pale blue or blue-violet;

floral tube 0.2–0.3 cm;

sepals pale violet, veined deep violet basally, ovate, 4–5 × 1.3–2 cm, base abruptly attenuate;

petals lavender, oblanceolate, 3.5–4.5 × 0.7–1.5 cm;

ovary trigonal, sharply angled;

style arched, narrow, 2–3 cm, crests divergent, quadrate, 0.5–0.7 cm, margins serrate;

stigmas sharply triangular;

pedicel somewhat flattened, 3–7 cm, exserted from spathe.

Capsules

prismatic to oblong-ovoid, obscurely 3-angled with obvious groove at each angle, 3.5–6 cm, beak 5 mm.

sharply 3-angled, almost winged, 3–4 × 1.2–1.4 cm, concave faces 6–14 mm wide.

Seeds

D-shaped, flattened, 6–7 mm, corky, lustrous.

in 1 row per locule, buff to dark brown, pyriform, with convex sides, 3–4 mm, smooth.

2n

= 34.

= 42.

Iris pseudacorus

Iris prismatica

Phenology Flowering Apr–Jun. Flowering Apr–Jul.
Habitat Swamps, wet shores of rivers and lakes Swampy, peaty soil
Distribution
from FNA
AL; AR; CA; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; ME; MS; NC; NH; NY; OH; PA; RI; SC; TN; VA; WA; WV; BC; MB; NB; NF; NS; ON; PE; QC; Eurasia; n Africa [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; CT; DE; GA; KY; MA; MD; ME; NC; NH; NJ; NY; RI; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 26, p. 390. FNA vol. 26, p. 395.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Laevigatae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Prisimaticae
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. pumila, I. purdyi, I. savannarum, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
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. pseudacorus, I. pumila, I. purdyi, I. savannarum, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
Name authority Linnaeus: Sp. Pl. 1: 38. (1753) Pursh: Fl. Amer. Sept. 1: 30. (1814)
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