Iris savannarum |
Iridaceae |
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prairie iris, savanna iris |
iris family |
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Habit | Herbs, perennial, rarely annual [or shrubs with woody caudex], evergreen or seasonal, sometimes cespitose; rootstock a rhizome, bulb, or corm. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Rhizomes | greenish, freely branching, forming large, open clumps, 2–2.5 cm diam., fleshy, with fibrous bases of old leaves not covering rhizome but persisting on ringlike scars. |
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Stems | 1-branched, solid, 3–10 dm. |
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Flowering stems | aerial (or subterranean in Romulea), simple or branched, terete or variously compressed, angled or winged. |
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Leaves | basal usually dying back shortly after anthesis, blade bright green, 6–10 dm × 0.8–2 cm, sometimes glaucescent; cauline with blade elongate, linear-attenuate, 15–20 cm, exceeding flowers. |
basal and cauline, distichous; proximal 2–3 sometimes membranous, not reaching much above ground; others with open or closed sheaths, usually unifacial [bifacial or terete], oriented edgewise to the stem; blade parallel-veined, plane or pleated, channeled. |
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Inflorescences/ |
1–3-flowered, branch units 1–2-flowered; spathes lanceolate, subequal or unequal, apex acute; outer 8–10 cm, herbaceous, margins scarious; inner 6–9 cm, completely scarious. |
umbellate, monochasial cymes (rhipidia), spikes, or solitary flowers; rhipidia enclosed in 2, opposed, usually large, leafy to dry bracts (spathes); flowers except for the first subtended by 1 floral bract; spike flowers each subtended by 2, opposed bracts. |
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Flowers | perianth blue to blue-violet (white in forma albispiritis); floral tube funnelform, 1.2–1.5 cm; sepals blue or pale violet with flecks of white and lines of deeper blue on either side of ridge, spatulate, elliptic to ovate, 7–8 cm, apex acuminate, ridge yellow, linear, extending to about middle of limb, finely pubescent, claw light green, striated, ribbed, 1–1.2 cm; petals erect or spreading-erect, deep blue, linear to narrowly linear-spatulate, 6–7.5 cm, base abruptly attenuate into claw, claw channeled, green with darker lines, margins pale; ovary bluntly 3-angled, ridged at each angle and on faces between angles; style linear-acute, 5–6 cm; crests ovate, 1–2 cm, margins sharply and irregularly toothed; stigmas broadly 2-lobed, margins crenate; pedicel 1.6–2 cm. |
usually pedicellate [± sessile]; perianth actinomorphic or zygomorphic, petaloid, with 2 equal or unequal whorls of 3 tepals each [1 whorl of 6]; tepals usually large, showy, distinct or connate in tube; stamens 3 [2], inserted at base of outer tepals or in tube, symmetrically arranged or unilateral, arcuate [declinate]; filaments distinct or partly to completely connate, sometimes weak, unable to support anthers; anthers with 2 pollen sacs, extrorse, occasionally latrorse, usually dehiscing longitudinally [rarely apically]; ovary inferior [superior in Tasmanian Isophysis], 3-locular [1-locular]; placentation axile [parietal]; ovules 2–few, anatropous; style single, filiform at least proximally, usually 3-branched or 3-lobed, branches either filiform, distally expanded, sometimes each divided in distal 1/2, stigmatic toward apices, or branches thickened, or flattened, petaloid, stigmas then abaxial below apices. |
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Fruits | capsular, loculicidal, rarely indehiscent, firm to cartilaginous, occasionally woody. |
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Capsules | ellipsoid, round in cross section, roundly 6-lobed, with 6 sharp, winglike, equally spaced ridges converging to form stout beak at apex, 6–10 cm, dehiscence loculicidal. |
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Seeds | in 1 row per locule, brown, circular or uneven, flattened, 8–12 mm diam, very corky. |
globose to angular (prismatic) or discoid, sometimes broadly winged; seed coat usually dry (rarely fleshy); endosperm hard, with reserves of hemicellulose, oil, and protein; embryo small. |
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2n | = 44. |
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Iris savannarum |
Iridaceae |
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Phenology | Flowering late Mar–early Apr. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Wet ditches, margins of lakes, streams, and swamps | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; FL; GA
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Nearly worldwide but rare in tropical lowlands; best represented in southern Africa |
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Discussion | Iris savannarum has often been included in I. hexagona, but differs in several ways. The capsules of I. hexagona are more obviously hexagonal, with smooth faces alternating with those that have two rounded lobes, whereas the capsules of I. savannarum are more rounded but with six obvious ridges, almost of winglike proportions. Iris hexagona has yellow-green leaves instead of the brighter green of I. savannarum. The leaves of I. savannarum die back after anthesis, while those of I. hexagona remain green. The flowering period of I. savannarum is almost one month earlier than that of I. hexagona in the area where both are known to grow. The sepals of I. savannarum are more acute at the apex than those of I. hexagona. Iris savannarum has been hybridized with Iris fulva to produce I. ×cacique (J. Berry) N. C. Henderson. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera ca. 65, species ca. 1810 (16 genera, 92 species; 9 genera, 19 species introduced, and various hybrid complexes in the flora). Iridaceae are currently divided into four subfamilies (P. Goldblatt 1990, 1991). Subfamily Isophysidoideae Takhtajan is monotypic, comprising the Tasmanian Isophysis T. Moore with a superior ovary. Only subfamily Iridoideae is native in North America. The remaining Nivenioideae Schulze ex Goldblatt and Ixioideae Klatt are centered in Africa south of the Sahara. Iridaceae are of considerable economic importance in ornamental horticulture and the cut-flower industry, especially Iris, Gladiolus, and Freesia. Several other genera (e.g., Crocus, Dietes, Sparaxis, Tritonia, Watsonia) are cultivated in gardens in both tropical and temperate areas. Moraea and Homeria are poisonous and pose significant problems in cattle- and sheep-raising areas, notably in southern Africa. In addition to the several genera and species escaped from cultivation and dealt with in detail below, the following are widely grown in areas of mild winter and may persist in and near abandoned gardens, sometimes reproducing successfully: Dietes Salisbury [D. iridioides (Linnaeus) Salisbury ex Klatt, D. grandiflora N. E. Brown]; Ixia Linnaeus (I. maculata Linnaeus, I. polystachya Linnaeus); Crocus cultivars and even some wild species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 26, p. 393. | FNA vol. 26, p. 348. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | I. albispiritus, I. hexagona var. savannarum, I. kimballiae, I. rivularis | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Small: Addisonia 9: 57, plate 317. (1925) | Jussieu | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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