(Question)
tree in mt. pleasant cemetery (toronto)
full sun, 30-40′ tall.
(Answer)
The tree from your photo appears to be Tilia mongolica (Mongolian Lime). The roughly, irregularly serrated leaf edge with its triangular teeth is a unique feature. This tree grows slower than other lindens with light grey, exfoliating bark. It grows best in full sun to part shade in alkaline, loamy, or well-drained soils. See this link for more information.