Viola septentrionalis Greene sensu stricto
Common names:
Northern Blue Violet
Synonyms:
Viola septentrionalis Greene, Pittonia 3: 334. 1898. Type: Canada. [Ontario] near Ottawa, 30 May 1898, J. M. Macoun 18761 (designated incorrectly as holotype by Landon McKinney, Sida, Bot. Misc. 7: 36. 1992; corrected to lectotype by Nir Gil-ad, Boissiera 53: 78. 1997): NDG33738 (n.v.), internet image; isolectotype: CAN119225 (n.v.)).
Viola septentrionalis Greene f. alba Vict. & J.Rousseau, Contr. Inst. Bot. Univ. Montreal 36: 20. 1940
Viola nesiotica Greene, Pittonia 5: 102. 1902
Viola subviscosa Greene, Pittonia 4: 293. 1901
Viola fletcheri Greene, Pittonia 4: 296. 1901
Viola macounii Greene, Pittonia 3: 335. 1898
Description:
Acaulescent rosulate perennials from thick rhizome, ≤ 29 cm tall; foliage and peduncles gray-green, upper surface of leaf blades darker green than lower, lower commonly tinged with purple, sparsely to densely hirsute; stipules free, irregularly glandular-fimbriate; leaves ascending to spreading, leaf blades undivided, largest ≤ 98 × 89 mm, narrowly or broadly ovate in chasmogamous flower, broadening to deltate-reniform in fruit, margins serrate (occasionally weakly so), densely ciliate with spreading hairs (these often long), apex acute to obtuse or rounded; chasmogamous peduncle held above the leaves early in fl, among the leaves later; chasmogamous flower ≤ 22 mm; calyx glabrous or pubescent, sparsely to densely ciliate nearly or fully to apex (hairs often long); lowest sepals broadly ovate-lanceolate to ovate or ovate-triangular, sharply acute or obtuse to rounded; auricles prominent and entire to erose, elongating to 3 mm in fruit; corolla blue to purple, throat white; spur short-globose; lateral petals densely bearded with filiform to narrowly linear hairs, spurred petal densely bearded; chasmogamous capsule green; cleistogamous flowers produced after chasmogamous, on prostrate peduncle much shorter than petioles and arching just before capsule dehiscence; cleistogamous capsule 5–8 mm, green drying tan with purple spots or blotches, glabrous; seeds 1.2–2.3 × 0.8–1.2 mm, light-medium brown to dark brown, unspotted; 2n=54.
Similar species:
The most similar violets likely to be confused with this species are Viola novae-angliae and Viola sororia sensu stricto, Borealiamericanae violets with densely pubescent foliage, undivided leaf blades, oblong to ovate ciliate obtuse to rounded sepals, and a heavily spotted or blotched cleistogamous capsule on a prostrate peduncle. This species differs from V. grisea in its narrowly ovate to ovate leaf blades with acute to rounded apex that broaden to deltate-reniform in fruit and have more uniformly serrate margins; and from V. sororia sensu stricto by its spreading-hirsute leaf blade margins, sepals ciliate to the apex and often hirtellous on the lamina, auricles prominent and elongating in fruit, densely bearded spurred petal, and seeds light to dark brown and unspotted (or with small weak darker streaks or spots in the Upper Midwest variant).
Ecology:
Thin sandy or gravelly loam soils in dry-mesic forests, on cliffs and ledges, commonly in limestone rubble or over dolomite or limestone bedrock, frequently growing under Thuja or Juniperus in the northern portion of its range.
Distribution:
Boreal and montane, interruptedly transcontintental, NL to BC, south to NJ, PA, along the higher elevations of the Appalachian Mountains to w. NC and e. TN; apparently disjunct in the nw. Rocky Mountains; reports from s. MI and s. WI are misidentifications of V. sororia.
Rarity:
State listed in NJ and WV.
Phenology:
Chasmogamous flower May–June, chasmogamous fruit June, cleistogamous fruit May–October.
Affinities:
This species belongs to the Acaulescent Blue Violet lineage, sect. Nosphinium W.Becker, subsect. Boreali-Americanae (W.Becker) Gil-ad, in the Sororia species group.
Hybrids:
Hybridizes with V. affinis (Brainerd 1904b, 1907a, 1924, House 1924), V. cucullata (Brainerd 1904b, 1924, House 1924), V. fimbriatula (Brainerd 1904b, 1905, 1924, House 1924), and V. sororia sensu stricto (Brainerd 1904b, 1924, House 1924). Brainerd reported that these exhibit intermediate or recombinant characteristics of foliage, chasmogamous flowers, cleistogamous capsules and seeds (where these did not abort). All hybrids fail to reproduce by chasmogamous flowers, and all either produce abortive cleistogamous capsules or capsules with very few viable seeds (up to 1/8 of ovules fertilized in the most fertile hybrid, with V. fimbriatula.
Comments:
Greene's protologue states that plants were collected from "Rich soil along the borders of thickets, near Ottawa, Ontario, in full petaliferous flower 10 May, 1898, and in fruit from the apetalous flowers a month later, J. M. Macoun; Canadian Survey n. 18,561." The protologue describes two different collections, does not refer to either as types, does not indicate that either collection is represented by a single sheet, and does not mention a herbarium. Only one sheet at NDG matches the protologue information precisely. McKinney first designated the NDG sheet incorrectly as the holotype; Gil-ad corrected this error to lectotype.
Brainerd (1921b), Brainerd Baird (1942), Fernald (1950), Henry (1953a), Russell (1965), Scoggan (1978), Strausbaugh and Core (1978), Gil-ad (1995, 1997, 1998), and Weakley et al. (2012) recognized this as a distinct species. Gil-ad presented a long list of macromorphological distinctions in leaves, chasmogamous flowers, cleistogamous capsules, seeds, as well as unique micromorphological features of lateral petal trichomes and seed coats, to support its maintenance as a species. Weakley et al. (2012) mentioned that its status and distribution in the central and southern Appalachians is obscure. Gleason and Cronquist (1991), Ballard (1995, 2000), Haines et al. (2011), and Little and McKinney (2015) synonymized it under V. sororia, while McKinney (1992) and McKinney and Russell (2002) subsumed it under V. sororia var. sororia.
Preliminary studies of herbarium specimens in the Thunder Bay District of Ontario south through eastern Minnesota then sporadically along the eastern border of Iowa suggest that populations in that region are somewhat divergent morphologically, and inhabit more acidic substrates; they are tentatively separately as Viola septentrionalis [Upper Midwest variant] for further study.
Literature Cited:
Alexander, E. J. 1963. Violaceae. In Gleason, H. A., The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. Hafner Publishing Co., Inc., New York, NY. 552-567.
Ballard Jr., H. E. 1995 ["1994"]. Violets of Michigan. Michigan Botanist 33: 131-199.
Ballard Jr., H. E. 2000. Violaceae. In Rhoads, A. (ed.). Flora of Pennsylvania. University of Pennsylvania Press, Philadelphia, PA. 700-710.
Brainerd, E. 1904b. Notes on New England violets. Rhodora 6: 8-17.
Brainerd, E. 1905. Notes on New England violets,-II. Rhodora 7: 1-8, Plate 50.
Brainerd, E. 1907a. Mendel's law of dominance in the hybrids of Viola. Rhodora 9: 211-216.
Brainerd, E. 1921b. Violets of North America. Vermont Agricultural Experiment Station Bulletin 224: 1-172.
Brainerd, E. 1924. The natural violet hybrids of North America. Vermont Agricultural Experiment Station Bulletin 239.
Brainerd Baird, V. 1942. Wild violets of North America. University of California Press, Berkeley, CA.
Fernald, M. L. 1950. Violaceae. In Gray's Manual of Botany, 8th ed. American Book Company, New York, NY. 1022-1042.
Gil-ad, N. L. 1995. Systematics and evolution of Viola L. subsection Boreali-Americanae (W. Becker) Brizicky. Ph.D. dissertation. University of Michigan, Ann Arbor, MI.
Gil-ad, N. L. 1997. Systematics of Viola subsection Boreali-Americanae. Boissiera 53: 1-130.
Gil-ad, N. L. 1998. The micromorphologies of seed coats and petal trichomes of the taxa of Viola subsect. Boreali-Americanae (Violaceae) and their utility in discerning orthospecies from hybrids. Brittonia 50: 91-121.
Gleason, H. A. and A. Cronquist. 1991. Violaceae. In Manual of vascular plants of northeastern United States and adjacent Canada, 2nd ed. New York Botanical Garden, Bronx, NY. 157-163.
Haines, A., E. Farnsworth, and G. Morrison. 2011. Violaceae. In Flora Novae Angliae. Yale University Press, New Haven, CT. 873-886.
Henry, L. K. 1953a. The Violaceae in western Pennsylvania. Castanea 18(2): 37-59.
House, H. D. 1924. Annotated list of the ferns and flowering plants of New York state. Family 83 Violaceae. New York State Museum Bulletin 254: 499-512.
Little, R. J., and L. E. McKinney. 2015. Violaceae. In Flora of North America: Cucurbitaceae to Droseraceae, 106. Oxford University Press, New York, NY.
McKinney, L. E. 1992. A taxonomic revision of the acaulescent blue violets (Viola) of North America. Sida, Botanical Miscellany 7: 1-60.
McKinney, L. E., and N. H. Russell. 2002. Violaceae of the southeastern United States. Castanea 67: 369-379.
Russell, N. H. 1965. Violets (Viola) of the central and eastern United States: An introductory survey. Sida 2: 1-113.
Strausbaugh, P. D. and E. L. Core. 1978. Violaceae. In Flora of West Virginia, 2nd ed. Seneca Books, Inc., Morgantown, WV. 644-658.
Weakley, A. S., J. C. Ludwig, and J. F. Townsend. 2012. Violaceae. In Flora of Virginia. BRIT Press, Fort Worth, TX. 963-975.
Chasmogamous flowering habit by Kim Blaxland, "Botanikim" website (permission granted by Chris Blaxland)
Chasmogamous flower front view by Kim Blaxland, "Botanikim" website (permission granted by Chris Blaxland)
Chasmogamous flower profile view by Arthur Haines, "Go Botany" website, Native Plant Trust
Chasmogamous fruit by Kim Blaxland, "Botanikim" website (permission granted by Chris Blaxland)
Seeds from herbarium specimen: Nova Scotia, North Sydney, Cape Breton, 26 Jul 1907, H. Robinson 611 (NY)
Seeds from herbarium specimen: Newfoundland, Valley of Exploits River, Bishop Falls, Boggy thickets, 28-29 Jul 1911, M. L. Fernald & K. M. Wiegand 5878 (VT)
Map of widespread members of the Sororia species group by Harvey Ballard