Curtain

And whan that hit ys eve, I renne blyve,
As sone as evere the sonne gynneth weste,

To seen this flour, how it wol go to reste,

For fere of nyght, so hateth she derknesse.

--Chaucer, Prologue to the Legend of Good Women. 

I still don't know how flowers go to rest,

how they draw petal over petal, as might
a man pull on his wretched coat at five;
I still don't know what muscles they contract,

or how they know that dusk has settled in.
I still don't even know what aim is served:
from what night ravening brutality
do they imagine that they save themselves?

But I do know how they feel when the dark
is drifting over lawn and field, and when
such beauty as they have is spread too wide;

each tender raw integument withdraws
and looks for shelter under every other; 
each eye desires a curtain and a close.