Poetry fun

Once every few weeks I play a poetry game with my creative writing class. I have a bin of words taken from various poetry books, random words that I like; dust, bamboo, spotless, sherbet...we each choose a word out of the box and use that word in a line of poetry. After the line is written we pass the word to the person next to us. My the time we have chosen four or five stanzas worth of words we have poems, using the same words. The poems are all completely different and fun to read out loud. Here is one of the first I wrote with my class.

Branches canopied over the deep forest floor -
a tent breaking the horizon into shards
of glass. The roots, selfless in
their hold, spring into amber twilight.

Imperfect buds wrap tightly,
ready to open purposefully when
clumsy Spring makes her appearance -
daffodils mirrored in muddy waters
while bullfrog bellies bloat.

Centuries of mating songs echoing
in dark damp earth. Nothing
prepares you for the closeted song -
females - choosy in their search for love
find solace in raspberry bushes
and the canopy of vines.

Can you figure out which words I was forced to use?