circle of understanding

Basically you get access to learn wizard spells but you your connection to evocation spells learnt both by wizards and druids is cut off by nature itself

Study of knowledge

When you choose this circle at 2nd level, you learn how to study spells and memorize them .But do not gain any when Levelling up as nature provides that magic, you must seek the magic that wizards derive from the world.

additionally the toll of studying has forced nature to only provide 2 spells per level and if the number of spell known exceed the spell slot limit, then the spell chosen will be from the wizard list.

Recovery of nature and study

Starting at 2nd level, you can regain some of your magical energy by sitting in meditation and communing with nature and revising your knowledge. During a short rest, you choose expended spell slots to recover. The spell slots can have a combined level that is equal to or less than half your druid level (rounded up), and none of the slots can be 6th level or higher. You can’t use this feature again until you finish a long rest

For example, when you are a 4th-level druid, you can recover up to two levels worth of spell slots. You can recover either a 2nd-level slot or two 1st-level slots.

circle spells

Your mystical and magical connection to the land and your study  infuses you with the ability to cast spells dedicated to your study. At 3rd, 5th, 7th, and 9th level you gain access to circle spells connected to the discovery of magic and understanding within your world. 

Once you gain access to a circle spell, you always have it prepared, and it doesn’t count against the number of spells you can prepare each day. the spells you gain access to are spells that may not appear on the druid spell list, the spell is nonetheless a druid spell for you.

3rd-clairvoiyance 

5th-scrying

7th-project image

9th-foresight

Wild Polymorph

Starting at 6th level, your wild shaping nature and polymorph studies have fused into a hybrid allowing you to become plants as well as beasts at the cost of the spell becoming a self cast.

Natures Gift

When you reach 10th level, you can befriend plants easily unless you have harmed it or it has an express purpose that drives it to fight you.

for example a treant protects a forest and will naturally want to kill you regardless if you provide harm to the forest s it would with any other adventurer.

enchanted Sanction

When you reach 14th level, you can infuse objects with the spell as long as you have the correct ingredients and for zero costs aside from the ingredients. the cost is that the object will now take twice as long to infuse. this can only be used once per long rest.