Common evening primrose (Oenothera biennis)
The long, four-parted woody fruit capsules of common evening primrose (Oenothera biennis) are readily recognizable even in winter. These capsules are arranged in spikes at the tip of the stem. Common evening primrose often grows as a single tall stem, 3 to 6 feet tall, but can develop multiple branches. In the case of a plant having more than one branch, each stem tip will produce a spike of flowers, and ultimately a spike of these woody capsules. The seeds…