Iris hexagona
Iris lacustris
Carolina iris, Dixie iris
dwarf lake iris
greenish with brown leaf scars, branching from older buds quite some distance proximal to apex, forming widely scattered colonies, 2–2.5 cm diam.
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.
1–2-branched, solid, 3–9 dm.
simple, 0.8–4 cm.
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 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.
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.
1(–2)-flowered;
spathes green, outer closely sheathing inner and enclosing ovary, slightly keeled at midrib, 4.5 cm, ± equal, margins scarious.
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 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.
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.
roundly triangular, 1.2 × 8 mm, enclosed in spathes.
in 2 rows per locule, light brown, D-shaped or irregularly rounded, 4–6 mm, corky.
dark brown, with white appendage spiraled around seed, ca. 3 mm, quickly drying when exposed to air.
= 44.
= 32, 42.
Iris hexagona
Iris lacustris
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.)
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.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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