Panax trifolius, dwarf ginseng, is a native perennial herbaceous plant. In any one season, an individual plant can produce either all bisexual (perfect) flowers or all male/staminate flowers. Dwarf ginseng has a very unusual life cycle. In subsequent seasons, the plant can undergoes "sex/gender change". It blooms late April/early May and greenish yellow fruits mature quickly. It is a true spring ephermal and in about 2 months it will be gone underground.

This is in our spring photo gallery collection.

Male/Staminate Inflorescence - flower cluster: 

The male plant is easier to spot because it flower head is larger and its shape is distinctive

Viewing from the top, the male (staminate) flower head looks ball shaped. The flowers mature starting from the bottom up so the buds are at the center. The third photo is a side view.

Male/Staminate - Individual flowers: 

The male flowers have fertile stamens. The female parts are sterile. The photos show a single short style but the pistil is sterile.

Bisexual/Perfect/Hermaphroditic - Individual flowers: 

The bisexual flowers have both fertile stamens and fertile pistils. The images below show bisexual flowers. The 5 stamens and 3 functional stigmas are apparent. The bisexual flowers are protandrous meaning the anthers are mature before the stigmas.

Since the plants are protandrous, in dwarf ginseng, it appears here that the finished stamens are completely discarded. We then have what appears to be female plants but are really bisexual plants. We found many plants where all the flowers had only pistils and no stamens. But occasionally, there would be a remnant of a shriveled up stamen indicating that there were stamens but they had fallen off.
The images below show flowers with fertile female stigmas and if you look hard, vestiges of a stamen are there. The pistil is compound with a 3-celled ovary with 3 stigmas. The stigmas are clearly seen. All the flowers on the plant were the same.

Bisexual/Perfect/Hermaphroditic - Inflorescence: 

The cluster of bisexual flowers is smaller with fewer flowers and can easily be distinguished in the field.

In this cluster, all the flowers have pistils and stamens

In this cluster, two of the 5 flowers have no stamens, all have pistils

In this cluster, none of the flowers have stamens, all have pistils

Life Cycle & Sex/Gender Change 

When the dwarf ginseng plants are very small they do not bear flowers and only produce leaves. When they are first large enough to have flowers, the flowers will be male. Producing pollen requires less stored energy. When the plants are large enough (have enough stored energy), they will produce bisexual flowers. These bisexual plants with functional pistils, after pollination, will be able to produce fruit and consequently will need more stored energy to support the seed production process. This has often referred to as a "sex change". After producing seed, the plant will in the following year most likely produce male flowers.

Studies have shown that the plants can alternate between the two different genders during their life time. It has been estimated that every year about one fourth to one third of the plants in an area switch from producing one kind of flower to the producing the other. This a rare sexual system.

Both forms of the plant produce viable pollen. Comparing the male plant stamens to the bisexual plant stamens, studies have shown that the male plants produce more flowers - 2-3 times more. The male plant anthers produce more pollen per anther, about 1.2 time more. The male plant pollen is available for a longer time and the timing coincides closely with the time the stigmas are ready. The bisexual plant stamens produce pollen for a shorter period of time and the pollen is available before the stigmas are ready discouraging self fertilization and favoring cross pollination by the male plants.

The petals fall off, the stigmas remain. Stamens are not apparent in the first photo below. In the first 2 photos, the leaves are still functional. The base of the flower, ovaries, expand. In the last 3 photos, the fruit may be ripening but resources from the leaves are diminishing. In the last photo, two fruits are ripening and two have aborted.

The single stem of the plant terminates in a whorl of compound leaves and a single flowering stalk close to the ground. The whorl of 3 leaves each with 3-5 leaflets. Individual leaflets are 0.75 to 1.5 inches long. The plant including the flower is about 3 - 8 inches tall. Underground, each plant has a small corm about the size of a pea which is the perennial energy storage part of the plant.

Additional information / references:

References on life cycle & "sex change":

Mark Schlessman has done many scholarly studies on dwarf ginseng. Here is one:

Article can be downloaded from here: https://www.researchgate.net/publication/271774861_Floral_Phenology_of_Sex-Changing_Dwarf_Ginseng_Panax_trifolium_L_Araliaceae 

Excellent readable discussion and gives many references: https://www.discoverlife.org/nh/tx/Plantae/Dicotyledoneae/Araliaceae/Panax/trifolium/

Article from Georgia: https://georgiabiodiversityportal.org/natels/profile?es_id=16616

Plant descriptions and photos:

This site always has good descriptions: https://www.minnesotawildflowers.info/flower/dwarf-ginseng

This site always has great photos : https://www.delawarewildflowers.org/plant.php?id=1382