Quote from this site
https://www.mushroom-appreciation.com/phoenix-oyster-mushrooms.html
“One of the key differences between the Phoenix oyster mushroom and the “true oyster,” P. ostreatus, is their fruiting season. The Phoenix prefers warmer weather – it usually fruits from April through September, appearing as soon as the weather transitions out of winter.
Pleurotus ostreatus, on the other hand, is a cool-season mushroom that won’t fruit until the weather cools down. This is an excellent way to determine which oyster mushroom you’ve found initially.”