Iris douglasiana |
Iris lacustris |
|
---|---|---|
Douglas' iris, mountain iris |
dwarf lake iris |
|
Rhizomes | freely branching, forming large colonies, slender, 0.8–0.9 cm diam., covered with remains of old leaves; roots fibrous. |
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. |
Stems | 1–4-branched, solid, 1.5–7 dm. |
simple, 0.8–4 cm. |
Leaves | basal with blade yellow-green, occasionally darker green, sometimes flushed pink or red basally, prominently ribbed, linear, 4.5–10 dm × 2 cm, apex acute; cauline 1–3, reduced. |
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. |
Inflorescence units | (2–)3-flowered, branch units 2–3-flowered; spathes opposite or separated, divergent, green, sometimes flushed purple basally, lanceolate-acuminate, 6–12 cm × 7–12 mm. |
1(–2)-flowered; spathes green, outer closely sheathing inner and enclosing ovary, slightly keeled at midrib, 4.5 cm, ± equal, margins scarious. |
Flowers | perianth deep red-purple, lavender, gray-blue, cream, or white, with gold signal and blue or purple veins; floral tube 1.5–2.8 cm, usually widening to bowl shape at base of flower; sepals oblanceolate to obovate, 5–9 × 1.4–3 cm, base gradually attenuate, apex obtusely rounded; petals oblanceolate, 4.5–7 × 0.9–1.8 cm, base attenuate to narrow claw; ovary elliptic-oval, sharply triangular in cross section, 3–4 cm; style 1.7–3.5 cm; crests overlapping, subquadrate, 1–2 cm, margins coarsely toothed; stigmas triangular; pedicel 2–5 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. |
Capsules | sharply triangular in cross section with ridge at each angle, tapering at both ends, remnant of floral tube forming tip at apex, 2.5–5 cm. |
roundly triangular, 1.2 × 8 mm, enclosed in spathes. |
Seeds | dark brown, pyriform, wrinkled. |
dark brown, with white appendage spiraled around seed, ca. 3 mm, quickly drying when exposed to air. |
2n | = 40. |
= 32, 42. |
Iris douglasiana |
Iris lacustris |
|
Phenology | Flowering Apr–Jun. | Flowering May. |
Habitat | Open woods, sunny slopes and fields | Moist, sandy gravel, limestone shores of lakes |
Distribution |
CA; OR
|
MI; WI; ON
|
Discussion | R. C. Foster (1937) named several varieties of Iris douglasiana, about which L. W. Lenz (1954) said, “This is a widespread and extremely variable species whose total variability is being increased due to introgressive hybridization between it and other species with which it has come into contact. Well marked and distinct geographic races cannot be detected; however, pronounced variations are to be found within a single population. For these reasons no attempt is made here to segregate taxa within such a polymorphic species.” Iris douglasiana hybridizes with I. bracteata, I. chrysophylla, I. fernaldii, I. hartwegii, I. innominata, I. macrosiphon, I. munzii, I. purdyi, I. tenax, and I. tenuissima. The natural hybrid between I. douglasiana and I. innominata has been designated as Iris ×thompsonii R. C. Foster and the garden hybrid as Iris ×aureonympha E. H. English. (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.) |
Source | FNA vol. 26, p. 384. | FNA vol. 26, p. 378. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | I. beecheyana, I. douglasiana var. alpha, I. douglasiana var. altissima, I. douglasiana var. beecheyana, I. douglasiana var. bracteata, I. douglasiana var. major, I. douglasiana var. mendocinensis, I. douglasiana var. nuda, I. douglasiana var. oregonensis, I. watsoniana | I. cristata subsp. lacustris, I. cristata var. lacustris |
Name authority | Herbert G. A. W. Arnott: in W. J. Hooker and G. A. W. Arnott, Bot. Beechey Voy., 395. (1840) | Nuttall: Gen. N. Amer. Pl. 1: 23. (1818) |
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