For some help on Identifying Ontario grasses here are some links that you might find helpful.
Ontario beef grass factsheet. Ontario Grasses.
I was amazed at the sheer number of grasses we have up here. Not just timothy or orchard, but indian, bottle-brush, rice cut, sedges, bromes, ryes and more. On the Ontario Grasses site you can look up via the common name or by the scientific name.
I learned when trying to identify what grass you have you need to observe a few things.
1. whether it is clumping or sod forming.
2. where it is located... land, near water etc.
3. seed head.
4. shape of stem and positioning of leaves.
For information on a broader Canadian Scale check out this link.
1. roughage for long stem fibre
2. rabbit's enjoyment
3. gut stabilization when giving medication.
4. part of a "giving extras" program - it becomes another treat for the rabbit.
5. part of a natural feeding method
6. assistance in helping bunnies through entropathic illness
Do you HAVE to feed hay?
If your pellets contain long-stem fibre, you do not. If they don't, you may wish to consider doing so. Many rabbits eat a pellet only diet and thrive. So not feeding hay is quite possible...but you NEED a good pellet.
Things to consider
Rabbits like hay. They do. :) Some rabbits will eat so much hay they won't eat their pellets. Then you need to consider where are they getting their needed trace nutrients that help them maintain optimal health. You may need to add salt and minerals to their diet, or reduce the amount of hay given to encourage a healthier eating style for your rabbits.
What type of grass should you feed?
1. the kind you can find.
2. the kind your rabbit likes to eat.
This site might also prove useful to you.