Elisa Gabbert’s “On Poetry” column features a wonderful look at cloud imagery in poetry and the poems of Reginald Shepherd are featured, along with the cover of The Selected Shepherd. “Reginald Shepherd is also a cloud-spotter. Almost every poem in THE SELECTED SHEPHERD (University of Pittsburgh Press, $30) mentions clouds, the way almost every painting in a landscape gallery mentions clouds. (There are paintings of clouds, and those that only mention them in passing.) Shepherd isn’t quite writing “nature poems,” as we might say of Wright. But no poem about the world escapes nature, and clouds often enter as pure image:…