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Violet Key Schematics

(Plants of New York and New England)*



This page complements the two keys to the violets which are presented on this website. One of the keys is a traditional, text only, dichotomous key. The other is an interactive, pictorial, dichotomous key, which includes both text and photographic images. Though these keys are not particularly long, and the number of species covered is not great, it is nevertheless possible for a reader to get lost in the details, and fail to understand the guiding logic employed. The logic of a key is instrumental in learning about the represented taxa (in this case, Viola species).

This page presents the outlines of the logic in a different format. Here, species are arranged into groups based on shared characteristics. The important characteristics for understanding the violets include the following:  growth form (stemmed or Stemmed), corolla color, leaf margin characters, (lobes or the absence of lobes), petal pubescence (bearded or not), stolon production or not, and spur length.

Groups 1 and 2 include species that produce stems, upon which flowers are borne. The remaining groups include species that do not produce above-ground stems. Group 3 includes the stemless species with white corollas. Groups 4 and 5 include stemless species with blue, lavender or purple corollas. Group 6 is an outlier, a single Stemmed species with yellow corollas.

Readers who wish to view additional characteristics may continue with one or both of the two keys featured here.

The source of most of these data are from the treatments in the Flora of North America.*


  Group 1:  Stemmed, leaves various, but not heart-shaped, annuals from a taproot.
    Viola arvensis -  sepals noticeably longer than the petals.

Viola tricolor -  sepals shorter to or equal to the petals.

  Group 2:  Stemmed, leaves heart-shaped, perennials from a rhizome.
    Viola canadensis  -  corollas white, bearded, spurs 1-2 mm. long.
Viola striata  
-  corollas white, bearded, spurs up to 4 mm long.
Viola labradorica  -
  corollas blue/violet,
bearded, spurs 4-8 mm long.
Viola adunca - corollas blue/violet, bearded, spurs 5-7 mm long.
Viola rostrata  -  corollas blue/violet, not bearded, spurs 7-12 mm long.
Viola pubescens  -  corollas yellow, bearded, spurs 1.0-2.5 mm long.
  Group 3:  Stemless, corollas white, margins unlobed, spurs 1-3 mm long.
    Viola blanda:   not bearded, stoloniferous, leaves ovate to rotund
Viola pallens:   bearded, stoloniferous, leaves ovate to rotund
Viola renifolia
:   sometimes bearded, not stoloniferous, leaves rotund to reniform
Viola lanceolata
:   not bearded, stoloniferous, lvs. lanceolate
Viola primulifolia
:   sometimes bearded, stoloniferous, lvs. lance-ovate to ovate
  Group 4:  Stemless, corollas blue/violet, margins unlobed.
    Viola odorata:   bearded, stoloniferous, spurs 5-7 mm long.
    Viola sagittata (var. ovata):   bearded, not stoloniferous, spurs 2-3 mm long.
    Viola cucullata:   bearded, not stoloniferous, spurs 2-3 mm long.
    Viola selkirkii:   not bearded, not stoloniferous, spurs 4-7 mm long.
    Viola affinis  bearded, not stoloniferous, spurs 2-3 mm long.
    Viola septentrionalis:  bearded, not stoloniferous, spurs 2-3 mm.
    Viola sororia:   bearded, not stoloniferous, spurs 2-3 mm long.
  Group 5:  Stemless, corollas blue/violet, margins lobed, not stoloniferous, spurs 2-3 mm long.
    Viola sagittata var.sagittata:  bearded
    Viola palmata:   bearded
    Viola brittoniana:   bearded
    Viola subsinuata:  bearded
    Viola pedata:  not bearded
  Group 6:  Stemless, corollas yellow, leaves ovate to rotund.
              Viola rotundifolia:  margins unlobed, bearded, spurs 1-2 mm. long.
* Source:  Flora of North America Editorial Committee, editors. Flora of North America,
        vol. 6.  Oxford University Press, New York, NY.

Page copyright  Arieh Tal, 2023.  All rights reserved.