Learn Farsi: بابونه یک گیاه دارویی محسوب می‌شود. - Chamomile is considered a medicinal plant.

No. In English, we often say something is considered "as" or "to be" something else. In Farsi, محسوب شدن takes the classifying noun phrase directly. You just say the item (بابونه), what it is classified as (یک گیاه دارویی), and then the verb (محسوب می‌شود). Adding a phrase like به عنوان (as) isn't grammatically necessary here, though you might occasionally hear native speakers use it anyway.

How would this sentence look if we used the other verb from this lesson, به شمار رفتن?

You would say: بابونه یک گیاه دارویی به شمار می‌رود. Both verbs mean "is considered" or "counts as," and both are formal. The main structural difference is that به شمار رفتن inherently contains the preposition به (to/at), while محسوب شدن is a straightforward compound verb without a preposition.

How is the adjective دارویی (dâru-yi) formed?

It is built from the noun دارو (dâru, medicine) plus the adjective-forming suffix ـی (-i), which means "related to" (creating "medicinal"). Because دارو ends in a long vowel (u), a connecting consonant sound (y) is added to make the transition smooth, giving us the spelling and pronunciation دارویی (dâru-yi).

I don't see an ezafe written here. Where does it go when spoken?