1929, Iris Chrysaeola
Addisonia, volume 14, page 9, plate 454, 1929
Native of southern Louisiana
Family Iridaceae, Iris Family
Another reward, in addition to Iris chrysophoenicia, discussed in a preceding article, was the additional new species here described. It grew in similar situations and was a somewhat larger plant, and although the flower is no richer in color, it is more varied in shades. Our knowledge of this showy iris is, moreover, not confined to the original collection, for Charles A. Mosier and the writer found it in additional localities in the same region both in the spring of 1926 and that of 1927.
Everything about this species is a profound secret, its genetic, geologic, and geographic history being alike obscure. The flower is so different from those of our other irises, even its companions, that they can scarcely be assigned a common ancestor. The much suffused colors of the sepals and the nearly equally six-ridged capsule mark it off very distinctly.
We may safely assume that this iris is an immigrant in its present habitats, for it must be much older than the present lower delta of the Mississippi River, though how old geologically we, of course, cannot say. Whether it came to its present haunts from the east, from the north, or from the west, is its own secret, for its former trails are now absolutely blotted out.
This iris may have a long life before it, but geographically it is at its last stand for it is right up against the Gulf of Mexico on the south and does not seem able to advance northward. It may be able to spread eastward or westward or both, but there is no evidence that it will do so. The fact that this iris now occurs on both sides of the present channel of the Mississippi River is no evidence in favor of an east- west migration, but merely indicative of a vacillation of the channel of the river from one side of the delta to the
Plants of Iris chrysaeola have proved to be hardy in cold-frames at The New York Botanical Garden, although thoroughly frozen and are also hardy in the open with only slight protection in the winter. In its native haunts it thrives best in full sunlight, along ditches and damp prairie-like spots. However, it sometimes occurs on the edges of the swamps in partial shade. The type specimen is in the herbarium of The New York Botanical Garden.
The gold-embroidered iris has a stout elongate rootstock which is often branched. The leaves are erect and more or less curved, mostly four to six at the base of the flower-stalk. The blades are linear-attenuate, mostly three-quarters to an inch wide, glaucescent, especially near the base. The flower-stalk is erect, about three feet tall, with one or two elongate leaves on the lower part and two or three shorter leaf-like bracts on the upper part, with the internodes somewhat flattened on the side opposite the leaves and the bracts, rounded on the other side, or angled below the base of the bracts, more or less glaucous. The involucre is of two main bracts, the outer one elongate and linear-attenuate, exceeding the flower, the inner (second) bract nearly or quite half as long as the outer one, scarious margined but green otherwise to the tip. The flowers are usually two together at the top of the stalk, single in the axils of the foliaceous bracts below the tip, the primary terminal flower with a pedicel one and a half to one and three-quarters of an inch long. The hypanthium surrounding the ovary is six-angled, dull, much shorter than the pedicel, which together with the hypanthium is completely enveloped by the involucre. The flower-tube is about as long as the ovary, several -ridged, shining. The three sepals are remate, three and a half to four inches long. The claw is shorter than the blade, broadest about the middle; without, yellowish-green and finely ridged; within, light-yellow or yellowish-green, finely ridged and more or less striate with greenish-purple on both sides of a rounded median ridge. The blade is oval-ovate, longer than the claw; without, the base and middle part greenish-yellow and purple- veined, the edges purplish and flecked with pale green; within, with a violet background, except the yellow median bearded crest and lateral parallel and thence radiating veins and flecks of yellow throughout except the terminal area. The three petals are broadly spatulate, two and three-quarters to three and one-quarter inches long. The claw is shorter than the blade, broad, cuneate, when spread out, above the short contracted base; without, striate, yellowish at the base, then green which merges into bluish-purple; within, yellow at the involute base, thence magenta-tinged, striate and slightly flecked below the blade. The blade is somewhat elliptic, longer than the claw, evenly violet except the darkveining and the often pale-flecked sides near the base. The style appendages are half -ovate, one-third to three-quarters of an inch long, unevenly toothed or jagged-toothed on the outer side and at the apex. The stigma is two-lobed, the lobes erose-toothed. The capsule is nodding, ellipsoid-ovoid, three to four inches long, bright-green, with six broad and rounded ridges, thick- walled. The seeds are numerous, in two rows in each capsule-cavity, one-third to one-half an inch broad, irregularly half -orbicular, uneven in thickness, brown, corky-walled.
John K. Small.
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