Oh alright so sometimes ποτερον isn’t present such as utrum. I see. I have also seen that many Ancient Greek sentences don’t contain every word that must be translated for it to sound like idiomatic English (such as the verb “to be,”).
Take a look at the accent over the η, and then take a look at the vocabulary list for 1J. As the feminine article, η has a rough breathing, but no accent.
If you are using Windows with the Polytonic Greek keyboard installed, there are some wierd key combinations you can use to get accents, breathings, an iota subscript, or some combination thereof.