Iris lacustris

Nuttall

Gen. N. Amer. Pl. 1: 23. 1818.

Common names: Dwarf lake iris
Endemic
Synonyms: Iris cristata subsp. lacustris (Nuttall) H. H. Iltis Iris cristata var. lacustris (Nuttall) Dykes
Treatment appears in FNA Volume 26. Treatment on page 378. Mentioned on page 373.

Rhizomes 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 simple, 0.8–4 cm. Leaves: 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 1 (–2) -flowered; spathes green, outer closely sheathing inner and enclosing ovary, slightly keeled at midrib, 4.5 cm, ± equal, margins scarious. Flowers: 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 roundly triangular, 1.2 × 8 mm, enclosed in spathes. Seeds dark-brown, with white appendage spiraled around seed, ca. 3 mm, quickly drying when exposed to air. 2n = 32, 42.


Phenology: Flowering May.
Habitat: Moist, sandy gravel, limestone shores of lakes

Discussion

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.

Selected References

None.

Lower Taxa

None.

"decreasing" is not a number."shorter and narrower" is not a number."dm" is not declared as a valid unit of measurement for this property.

... more about "Iris lacustris"
dehiscing +  and latrorse +
Norlan C. Henderson +
Nuttall +
16 cm160 mm <br />0.16 m <br /> (4 cm40 mm <br />0.04 m <br />) +
10 cm100 mm <br />0.1 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Iris sect. Limniris +
additional +
cordlike +
enlarging +
1.2 cm12 mm <br />0.012 m <br /> (?) +
triangular +
8 cm80 mm <br />0.08 m <br /> (?) +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
Dwarf lake iris +
linear +  and semiovate +
monochasial +
Ont. +, Mich. +  and Wis. +
3 cm30 mm <br />0.03 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.8cm;1.2cm +
distinct or;partly completely connate +
hollow +  and solid +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
sessile +  and pedicellate +
fragrant +
upward-facing +
hollow +, solid +, branched +  and simple +
flattened +, terete +  and cordlike +
indehiscent +  and loculicidal +
woody;firm;cartilaginous +
Moist, sandy gravel, limestone shores of lakes +
multicellular +
distinct +
cauline +  and basal +
bractlike +  and scale-like +
distinct +
triangular +  and rounded +
6-angled +, 3-angled +  and terete +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
4 cm40 mm <br />0.04 m <br /> (18 cm180 mm <br />0.18 m <br />) +
differentiated +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
reduced +
0.4 cm4 mm <br />0.004 m <br /> (?) +  and 0.5 cm5 mm <br />0.005 m <br /> (?) +
Flowering May. +
2 cm20 mm <br />0.02 m <br /> (?) +
Gen. N. Amer. Pl. +
heterogeneous +
heterogeneous +
-white +  and yellow- +
toothed +
tan;dark-brown +
conspicuously roughened +  and extensively corky +
4 +  and 20 +
rounded;flattened +
reflexed +  and spreading +
tapering +
expanding +
0.8 cm8 mm <br />0.008 m <br /> (?) +
persisting +
inner +  and outer +
4.5 cm45 mm <br />0.045 m <br /> (?) +
monochasial +
0.8 cm8 mm <br />0.008 m <br /> (4 cm40 mm <br />0.04 m <br />) +
3-lobed +  and filiform +
1 cm10 mm <br />0.01 m <br /> (?) +  and 2 cm20 mm <br />0.02 m <br /> (?) +
Iris cristata subsp. lacustris +  and Iris cristata var. lacustris +
Iris lacustris +
Iris sect. Lophiris +
species +
connate +  and distinct +
scarious +
spathaceous +  and more-flowered +
obscure;prominent +
hardened +  and papery +
unequal +