Viola rotundifolia
Viola palustris
early yellow or roundleaf yellow violet, round-leaf violet, roundleaf yellow violet, violette à feuilles rondes
alpine marsh violet, marsh violet, northern marsh or marsh or swamp or alpine marsh violet, northern marsh violet, violette des marais
basal, 2–5, prostrate to ascending, often overlapping basally;
stipules linear-lanceolate, margins entire, apex acute;
petiole 2–8 cm, pubescent;
blade unlobed, orbiculate, reniform, or ovate, 2–12 × 1.5–9 cm, base cordate, margins crenate to serrate, sometimes glandular, ciliate or eciliate, apex rounded to acute, surfaces usually pubescent throughout or concentrated proximally on both surfaces.
basal, 2–4, ascending to erect;
stipules linear-lanceolate, margins entire, apex acute;
petiole 1–17 cm, glabrous;
blade unlobed, reniform or ovate to orbiculate, 0.5–6.4 × 0.5–5.5 cm, ± as long as wide, base cordate, margins crenulate, eciliate, apex obtuse to acuminate, surfaces glabrous.
1.5–7 cm, usually pubescent.
2–20.7 cm, glabrous, bracteoles usually below middle in chasmogamous flowers.
sepals lanceolate to ovate, margins ciliate or eciliate, auricles 0.5–1 mm;
petals deep lemon-yellow on both surfaces, lower 3 brownish purple-veined, lateral 2 bearded, lowest 8–11 mm, spur yellow, gibbous, 1–2 mm;
style head beardless; cleistogamous flowers on prostrate or partially subterranean rhizomes or on racemelike, nonrooting, and usually leafless branches growing from rhizome apex.
sepals ovate or lanceolate, margins eciliate, auricles 1–2 mm;
petals lilac, pale blue, or pale violet on both surfaces, sometimes nearly white and tinged with lilac, lowest and sometimes lateral 2 dark violet-veined, lateral 2 bearded or beardless, lowest 8–16 mm, spur usually same color as petals, gibbous, 1–3 mm;
style head beardless; cleistogamous flowers on ascending peduncles.
ellipsoid, 5–10 mm, glabrous.
ellipsoid, 6–10 mm, glabrous.
beige, 1–2 mm.
dark brown, 1–2 mm.
= 12.
= 48.
Viola rotundifolia
Viola palustris
N. H. Russell (1955b) stated that Viola rotundifolia is a primitive member of Viola and probably one of the ancestral species of stemmed yellow violets of North America. Russell (1965) stated that morphologically, V. rotundifolia is one of the most invariable violets and suggested that its nearest relative is V. orbiculata.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Viola palustris occurs in small colonies; individual plants are interconnected by stolons. When flowering, usually three or more leaves are present per caudex.
M. Sorsa (1968) noted that in western North America Viola palustris specimens differ from European V. palustris plants and often show variation in character combinations. She stated (pers. comm.) that North American V. palustris is not a uniform entity.
E. Hultén (1968) synonymized Viola palustris with V. epipsila, as did W. J. Cody (2000). G. W. Douglas et al. (1998–2002, vol. 5) recognized both species. We assume that V. palustris does not occur in Alaska; verification is needed. See additional discussion under 18a. V. epipsila var. repens.
M. Sorsa (1968) indicated that Viola palustris var. brevipes has often been confused with V. blanda and that var. brevipes may have arisen from hybridization between a tetraploid and a diploid plant. Listed here in synonymy, var. brevipes may warrant recognition.
Reports of Viola palustris from one location in Coconino County, Arizona, first collected in 1962, likely refer to V. macloskeyi.
Viola palustris hybridizes with V. epipsila var. repens (M. Sorsa 1968; T. Marcussen and T. Karlsson 2010).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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