In order to correctly identify violets the following features must be examined :
these are stems, leaves and flowers.
Stems :
Above-ground stems are :
acaulescent (stemless) caulescent (stemmed)
In acaulescent species the rhizomes or stolons gives rise to a crown of basal leaves and flowers. Care should be taken to assess the position of leaves since some species (i.e. Viola adunca and Viola labradorica - caulescent species) may have very short (less than 1 cm) stems at flowering and may appear acaulescent.
Below-ground stems are :
slender rhizome stout rhizome taproot
Rhizomes are slender (mostly 1 to 3 mm thick) and travel horizontally underground, or stout (mostly 4 to 6 mm thick) and are usually oriented vertically underground - these are the perennials. Annuals have a vertical, fibrous root known as a taproot. To evaluate a slender versus a stout rhizome in the field, just place your thumb and index vertically around the base of a plant, near the soil. If your thumb and finger touch, then you have a slender rhizome, otherwise the rhizome is stout.
On-the-ground stems are :
Stolon
Stolons are horizontal stems that may be naked or with small leaves. These are usually not produced until after flowering and care should be taken to assess their presence with old (last year's) stolons.
Leaves :
Shape
reniform broad cordate-ovate cordate-ovate lanceolate
Base
broadly cuneate truncate cordate
Margin
crenate serrate
The margin is often identified by a combination of features, i.e crenate-serrate.
Pubescence
glabrous strigose pilose
Petioles
pubescence winged (w) or not
Flowers :
Corolla
Petals
u - upper petals; l - lateral petals; s - spurred petal
'Bearded' petals round (clavate) hair
'Bearded' petals pointed hair
Sepals
a - auricle; e - eciliate; c - ciliate (resemble short eyelashes)
Style and stigma and ovary
The identification of infrageneric groups of violets is possible by looking at the style, the stigma and the ovary. The ovary can be with or without hairs. The style may be very bent, slightly bent, or not bent ; it can be thin and uniform in thickness or distinctly enlarged near the apex. The apex can be with or without hairs ; various forms of the stigma are present. Use your 10 x hand lens to identify the features of the flower...this takes a steady hand.
Other features
Capsules and seeds are often used to separate the violets, but they require higher magnification from a microscope. They are not presented here.
Violets produce in early or mid-summer a second type of flower that does not bear petals and does not expand. These are called cleistogamous flowers. They can be used to identify violets but are usually combined with stem and leaf characters...these types of flowers should be left to enthusiasts and experts.
Top of Page
Violet Intro; Key to Violet/Purple/Blue; Key to White; Key Yellow & Multicolored
Back to the NB Botany Club website