Could Oenothera triloba and Himalayan Dandelion possibly be the same plant? It seems that gardeners confuse the two of them.
I understand the confusion as there appears to be a lot of mislabelling of images and confused discussions online but I do not think that if correctly labelled they are the same plant.
Oenothera triloba or stemless evening primrose is a member of Onagraceae, or evening primrose family, which includes evening primroses, which flower at night, and sundrops, which flower during the day. Oenothera triloba is an annual native to the Southern US and Mexico. The flowers of the plant have four petals. Here is a link to a US Department of Agriculture data base entry on the plant https://plants.usda.gov/core/profile?symbol=oetr2
Himalayan Dandelion, on the other hand, is the name correctly given to a member of the genus Taraxacum, of the family Asteraceae, which includes the species called dandelions. Dandelions are found all over the world; more than 150 species of dandelions in the Himalayan area alone. They are perennial plants, generally with short stems, with simple or lobed leaves forming a basal rosette. The plant has very dense flowerheads with a ray of florets. They are typically open in the daytime but closed at night. Here is a link to a description of White Himalyan Dandelion (https://www.flowersofindia.net/catalog/slides/White%20Himalayan%20Dandelion.html)
The confusion between the plants is somewhat understandable as there are some similarities between the plants. They both typically have yellow flowers which rise from a rosette of narrow lobed leaves. However they are really quite different. The dandelion has a dense flower head with rays of florets. It is open during the day. Evening primroses have simple flowers, generally with only 4 petals and are open at night.