and the seeds taste similar, but I can't find any mention of such a tall variety.
Don't eat the seeds of an unidentified plant that looks like parsley!
The parsley/carrot family includes some very poisonous plants, including Poison Hemlock (Conium maculatum) and Water Hemlock (Cicuta maculata). Having taken a closer look at the leaves in your photos, I can say it's not poison hemlock or water hemlock (fortunately). However, until you figure out what plant it is, don't eat any more of it.
The same family also includes giant hogweed (Heracleum mantegazzianum) and other related plants whose sap can cause skin blistering or rashes. Even some of the food plants in this family have sap that you should avoid getting on your skin, or wash it off quickly if it does.
Just because it's in your garden doesn't mean it's a food plant. Plants get into gardens in many ways: on your boots, on gardening equipment, stuck to the feet and fur of wildlife, in the guts of birds, falling over the fence from your neighbor's property, seeds planted by a previous resident and lain dormant in the soil until now, etc.
Also, don't eat any part of an unidentified plant. The correct order of operations is:
- Identify what kind of plant it is.
- Figure out which parts are edible, and how they should be prepared to be edible.
- Harvest those parts of the plant, and prepare them in the necessary manner.
- Then eat them.
Don't skip any of the early steps.