The plant produces a (great/large/huge) 'mass of' blossoms every spring. = The plant produces 'masses of' blossoms every spring.
The mayor is trying to encourage more commuters to use 'mass transit' in order to alleviate traffic in the city.
His policies are supported by 'the' (great/broad) 'mass of' the people. [=by most of the people]
(..) - A good quiz question. I should check that one out. Of all the people on the films, his appearance has changed the least over the years. There's still a mass of unruly white hair and the beard and mustache... ...and always a ready smile. He's one of the most comfortable people to have around. (..)2012 The Hobbit: An Unexpected Journey
(..) And cut! What's happened at this point is that Gandalf, he's lit a pine cone... ...and he's thrown a pine cone down into the Wargs. The whole mass of Wargs is down here going crazy. And they've made these pine cones that-- Pine cone-shaped and had real little lights going all the way around. (..)2012 The Hobbit: An Unexpected Journey
(..) It is a burden he should never have had to bear. -We can ask no more of Frodo. -Gandalf,the enemy is moving. Sauron's forces are massing in the East. His Eye is fixed on Rivendell. And Saruman,you tell me,has betrayed us. Our list of allies grows thin. His treachery runs deeper than you know. (..)2001 The Lord of the Rings: The Fellowship of the Ring