Transformational Gardening


Northern Evening Primrose (Small-Flowered Evening Primrose) (Oenothera parviflora): Images

Date Location Notes Images
September 13, 2011 Southeastern, New Hampshire This evening primrose had fruit that is round-angled (not squarish, sharply-angled like Meadow Evening Primrose (Oenothera pilosella). The fruit is thickest near the base and tapers. The flowers are yellow. This means that the plant was either Common Evening Primrose (Oenothera biennis) (or one of its variations) or Northern Evening Primrose (Oenothera pariflora) (or one of its variations). The main differences appear to be the size of the seeds and how the two sepal appendages connect to the sepal.

Looking at the picture on the left hand side of the 2nd row, it appears that the two sepal appendances connect below the apex of the sepal. The apex of the sepal is the point furthest away from where the sepal attaches to the flower. There is a significant-sized ridge at the apex of the sepal and the appendances are attached beneath that ridge.

In addition, the seeds of Common Evening Primrose are 1.2 to 1.8 mm long and the seeds of Northern Evening Primrose are 1.8 to 2.2 mm long. As you can see from the picture on the right of the second row, it appears that the seeds are approximately 1.8 to 1.9 mm long when measuring from the center of each black hash mark that represents 1 mm.

Finally, a variation of Northern Evening Primrose is Oakes Evening Primrose (Oenothera oakesiana). Oakes Evening Primrose, which is found primarily from Massachusetts and south to Virginia, is covered with minute, stiff and appressed gray or white hairs. But this plant has an intermingling of short and long hairs which is commonly seen in the Northern parviflora variation.