The product at that link did not provide a botanical name :
W316. CUTTING CELERY-AFINA (63 days)
This hardy annual can be used in place of celery and is easier to grow. The
fine green leaves and thin hollow stems are especially good to flavor soups
and stews. About 18" tall. Both stocks and leaves are cut at a younger, more
tender stage than regular celery. 400 seeds
I tried Afina in Google and was rewarded with many
pages-full of some computer in various languages, so
tried "cutting celery" which provided Apium graveolens,
including a thumbnail photo - unfortunately it did not