Iris hexagona
Iris missouriensis
Carolina iris, Dixie iris
Rocky Mountain iris, western blue flag
greenish with brown leaf scars, branching from older buds quite some distance proximal to apex, forming widely scattered colonies, 2–2.5 cm diam.
freely branching, producing large colonies, stout, 2–3 cm diam., clothed with dark remnants of old leaves;
roots fleshy.
1–2-branched, solid, 3–9 dm.
simple or 1–2-branched, solid, 2.5–6 dm.
basal stiffly erect, blade yellow-green, lightly ribbed, 8–9 dm × 2–3 cm;
cauline 1–2, foliaceous, blade 1.2–2 dm, exceeding subtended flower.
basal with blade light green, often white basally, not prominently veined, linear, 4.5–6 dm × 0.3–1.2 cm, glaucous, apex acute;
cauline 2–3, often shed with spent stem, similar to basal leaves, distal may subtend branch.
1–2-flowered, branch units 1-flowered;
spathes lanceolate, subequal or unequal, apex acute;
outer foliaceous, 15–20 cm, usually exceeding flower;
inner 8–10 cm, herbaceous, with scarious margins.
with terminal and lateral units (when present) (1–)2–3-flowered;
spathes subopposite to distant, to as much as 3–7.5 cm apart, lanceolate or ovate, keeled, outer usually shorter, 3.5–4 cm, inner 5.5–7 cm, scarious with herbaceous areas basally and along keel, apex acuminate.
perianth blue to violet, rarely white;
floral tube funnelform, grooved in line with grooves of ovary, 2–3 cm;
sepals spreading horizontally, obovate to oval, 8–8.5 × 4 cm, claw greenish with prominent yellow midrib which is pubescent on each side at base, apex rounded;
petals erect or spreading-erect, oblanceolate to spatulate, 7–9 × 2 cm, claw veined with green;
ovary roundly triangular in cross section, with wide grooves at angles and concave sides, 2–3 cm;
style convex laterally from central reddish ridge, 3.5–5 cm, narrower than claw of sepals, crests erect, overlapping, semiovate to triangular, 1–5 cm, margins coarsely toothed;
stigmas 2-lobed, lobes triangular or rounded-deltoid, margins entire;
pedicel 2.5–3.5 cm.
perianth blue to lavender to white, veined deeper violet;
floral tube green with purple veins in line with midrib of petals, funnelform, constricted above ovary, 0.5–1.2 cm;
sepals deeply veined lilac-purple, with yellow-white signal at base of limb, claw yellowish white, veined and dotted with purple, obovate, 3.7–7 × 1.2–3.2 cm;
petals slightly divergent, oblanceolate to spatulate, 3.6–7 × 0.5–1.2 cm, base gradually attenuate, apex acuminate or rarely emarginate;
ovary trigonal with 6 shallow ridges, 1–2 cm;
style 2.4–4 cm, crests quadrate, 0.7–1.4 cm, margins irregularly toothed;
stigmas 2-lobed, margins entire;
pedicel slender, 1–6 cm at anthesis, increasing to 7.5–8 cm at maturity.
hexagonal in cross section, with 3 alternate sides plane, others with 2 rounded ridges with shallow groove between them, 2.5–3.5 × 2–2.5 cm.
almost circular in cross section, with 6 obvious, equidistant ridges, 4–5 × 1.5 cm.
in 2 rows per locule, light brown, D-shaped or irregularly rounded, 4–6 mm, corky.
light brown, nearly globular to pyriform, 4–4.5 mm, wrinkled.
= 44.
= 38.
Iris hexagona
Iris missouriensis
Iris hexagona is one of the rarest of all our native irises. We had seen herbarium specimens from seven localities in five counties of South Carolina. In searching for living plants at each of these sites we found that six of the seven are now under the water of Lake Moultrie. After extensive searching, one small population has been located at the other site, in a state park at Charleston, which is being watched carefully by the rangers of the park. A good-sized population has since been found in Dixie County, Florida, north of the small town of Shamrock, and another in neighboring Taylor County. These two populations are in the drainage system of Georgia, which in turn is fed by some of the streams from South Carolina. So far, though, I. hexagona has not been found in Georgia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The ecological range of Iris missouriensis is probably more varied than that of any other North American species of the genus, extending from almost sea level in southern California to 3000 m in Montana and Wyoming. There is correspondingly wide variation in a number of characters, which has caused much confusion as to taxonomic circumscription. Homer Metcalf (pers. comm.) made a detailed study of this species. The basic requirement for its success seems to be an extremely wet area before flowering and then almost desertlike conditions for the rest of the summer.
In large populations, sometimes covering hundreds of acres, Iris missouriensis may be found with either simple or branched stems, leaves from 4 mm to more than 1 cm wide, shorter than the stem or longer, only one flower to as many as three on a stem, and colors from deep blue to almost pure white. A single plant found on the Pariah Plateau in Kane County, Utah, with leaves only 3–4 mm wide and a single flower stem only 4 cm long, which meant that the flower was at almost ground level, was named Iris pariensis. No other such specimen has been located, and this entity must be considered as just an aberrant form that was due to the desertlike conditions in which it was growing.
Iris missouriensis is known to hybridize with I. longipetala.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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