Mitchella repens, partridgeberry, is a creeping / trailing native woody perennial plant that has evergreen leaves. It grows in the woodlands and forms low mats about 2" high. It blooms late spring - early summer. Frequently partridgeberry is classified as a woody (shrub) plant because it's above ground runners are woody to over winter.
The small trumpet shaped flowers are about a third inch across.
The partridge flowers are distylous. This means that there are two types of flowers based on the length of the styles (female) relative to the stamens (male). Each form on different plants . This is for cross-fertilization. In the photo below, the stigmas can be seen extending beyond the flower petals so the style is longer than the stamens. The second photo shows a disected flower and one can see the longer style and the shorter stamen further down in the flower. This is called the "Pin" form.
In the photo below, one can see the 4 stamens extending beyond the petals and the style is shorter and can not be seen. The next photo shows a disected flower and one can see the longer stamens and the shorter style further down in the flower. This form is called 'Thrum'.
The purpose of this distyly feature in the plant is for cross-pollination. interestingly only pollen from long stamen plants can successfully pollinate stigmas of long style plants. Similarly, pollen from short stamen plants can successfully pollinate stigmas of short style plant. Other combinations are not successful in producing seed. The flowers have a ring of nectary glands just above the ovaries to reward insect pollinators.
We have a patch of 'pin' flowers in our wooded yard and we found the 'thrum' form not far awat in a neighbor's yard. I checked the two patches and it appears that they are all the same type within the patch. We noticed that in our yard, even though we had lots of flowers, we only had one or two berries. Now we know why. We introduced some 'thrum' plant into our patch and will wait and see if it survives and if there are more berries.
From the photos above, it can been seen that the flowers occur in pairs. The base of the 2 flowers are fused. The fused ovaries produce one red berry-like fruit with two dimples from the two flower structures. The flowers have 4 petals, 4 stamens, and 4 stigmas (hard to see) on one style. The oblong fruit has 8 seeds from the two flowers.
Leaves and growth habit
The leaves are opposite with smooth margins and are around a half inch long. They are evergreen and the older leaves are slightly leathery. Notice the whitish vein down the middle of the leaves. The partridgeberry makes an attractive groundcover and is often used as a terrarium plant.
All photos by H & M Ling
Additional information / references:
This is Virgina Native Plant Society's Wildflower of the Year article on Partridgeberry: http://vnps.org/wildflowers-of-the-year/2012-partridge-berry-mitchella-repens/ It discusses the two forms of flowers and pollination as well as other information
Minnesota Wildflowers describes the plant in a nice format. to help identification. It has good photos showing both types of flowers. It also has reference to more technical information: https://www.minnesotawildflowers.info/flower/partridgeberry