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slender blue iris

savannah iris

Rhizomes

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.

extensively branching, to 12 × 0.5–0.7 cm, becoming 1.5–2 cm diam., with coarse, strongly ribbed, brown, scalelike leaves.

Stems

simple or 1–2-branched, 3–8 dm.

simple or rarely 1-branched, 3–7 dm.

Leaves

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

cauline 1–4, erect.

basal with blade green, often with red-brown margins, lightly ribbed, linear-ensiform, 3–5 dm × 1.5–2.3 cm, glaucous, apex acute;

cauline 2–3, spreading, blade narrowly linear, 0.5–0.7 cm wide, apex acute.

Inflorescence units

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

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

1-flowered, branch unit (if present) 1-flowered;

spathes covering pedicel, ovary, floral tube, and base of sepals, unequal, outer 3 cm × 10 mm, inner 6 cm × 10 mm.

Flowers

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.

perianth blue-violet;

floral tube with brown striations, funnelform, 2–2.5 cm;

sepals blue-violet with deeper veins, with yellow-white signal, orbicular, 7–8 × 3–4 cm, base abruptly attenuate into whitish claw with yellow-brown veining;

petals mostly hidden by bases of sepals, much reduced, 1.5 × 0.3–0.5 cm, bristle absent;

ovary trigonal, with shallow groove at each angle, 1.5 cm;

style 3.5–4 cm, crests linear to subquadrate, 1–1.8 cm, margins sometimes incised;

stigmas semicircular, margins entire;

pedicel 2–3.5 cm.

Capsules

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

globose to oblong, obtusely 3-angled, with rounded angles, 2.5–4 × 2 cm, rounded basally, abruptly contracted into beak apically.

Seeds

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

in 1 row per locule, dark red-brown, semicircular, flattened, 6–8 mm;

seed coat thick.

2n

= 42.

= 40.

Iris prismatica

Iris tridentata

Phenology Flowering Apr–Jul. Flowering May–Jun(–Oct).
Habitat Swampy, peaty soil Rich, swampy, shaded places, usually along coastal plain
Distribution
from FNA
AL; CT; DE; GA; KY; MA; MD; ME; NC; NH; NJ; NY; RI; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; NC; SC; TN
[WildflowerSearch map]
[BONAP county map]
Discussion

Iris tridentata is quite different from the other two species of ser. Tripetalae that occur in the flora. The rhizome has been described by W. R. Dykes (1913) as “almost stoloniferous,” by J. K. Small (1933), “the cord-like rootstocks are peculiar,” and by R. K. Godfrey and J. W. Wooton (1979), “clothed with coarse, strongly many-ribbed, brown, overlapping scales.” The brown scalelike leaves are produced very close together and are long enough that they appear as a small fan; as the internodes elongate, the scales are pulled apart but still overlap along the rhizome. Roots are produced from the lower side of the rhizome at the nodes. Branches may appear at any node along the narrow portion of the rhizome rather than just from the broader apex.

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

Source FNA vol. 26, p. 395. FNA vol. 26, p. 380.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Prisimaticae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Tripetalae
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. 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
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. verna, I. versicolor, I. virginica
Synonyms I. tripetala
Name authority Pursh: Fl. Amer. Sept. 1: 30. (1814) Pursh: Fl. Amer. Sept. 1: 30. (1814)
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