Viola
Family: Violaceae
Viola image
Walter Fertig
  • VPAP
  • Gleason & Cronquist
  • Resources
JANAS 33(1)
PLANT: Caulescent or acaulescent annual or perennial herbs. LEAVES: simple, dissected or compound, basal, cauline or both, stipulate, petiolate, alternate or opposite. INFLORESCENCE: flowers solitary, axillary or scapose. FLOWERS: sepals subequal, auriculate at base; petals unequal, the lower petal shorter or longer than others, the base elongated into a spur or gibbous on underside; lateral 2 petals generally spreading, generally bearded at base; upper 2 petals equal, erect or spreading; lower 2 stamens with nectaries projecting into the spur or sac; cleistogamous flowers present in many spp. FRUITS: ovoid to oblong, glabrous or hairy. SEEDS ca. 15‑20, usually ovoid, with a prominent caruncle. NOTES: Ca. 400 spp.; worldwide. (Latin: Viola, a classical name.) Clausen, J. 1964. MadroƱo 17:173‑197. REFERENCES: Little, R. John. Violaceae. 2001. J. Ariz. - Nev. Acad. Sci. Volume 33(1).
Vascular plants of NE US and adjacent Canada
Sep usually with posterior auricles; pet somewhat unequal, the 2 lateral ones often bearded internally at the base, the lower one usually with a basal spur or sac and sometimes bearded at the throat; stamens 5, the 2 lowermost bearing appendages that extend into the spur of the lower pet; ours herbs with axillary or basal 1-fld peduncles bearing 2 small bracts near the middle. Most spp. produce normal petaliferous fls in spring, and very fertile cleistogamous fls in summer. All spp. with cyanic (rather than yellow) fls produce occasional white-fld forms. Hybrids between closely related spp. are common, and spp. 3-8 form an intergrading polyploid complex. 400, mainly N. Temp.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.
Species within inventory project: Intermountain Regional Herbarium Network
Viola adunca
Image of Viola adunca
Viola arvensis
Image of Viola arvensis
Viola aurea
Image of Viola aurea
Viola beckwithii
Image of Viola beckwithii
Viola canadensis
Image of Viola canadensis
Viola charlestonensis
Image of Viola charlestonensis
Viola clauseniana
Image of Viola clauseniana
Viola frank-smithii
Image of Viola frank-smithii
Viola lithion
Image of Viola lithion
Viola macloskeyi
Image of Viola macloskeyi
Viola nephrophylla
Image of Viola nephrophylla
Viola nuttallii
Image of Viola nuttallii
Viola odorata
Image of Viola odorata
Viola palustris
Image of Viola palustris
Viola praemorsa
Image of Viola praemorsa
Viola purpurea
Image of Viola purpurea
Viola sororia
Image of Viola sororia
Viola tricolor
Image of Viola tricolor
Viola trinervata
Image of Viola trinervata
Viola utahensis
Image of Viola utahensis
Viola vallicola
Image of Viola vallicola