Origin of cluster cup
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for cluster cup
The first form met with in most rusts is sometimes called the “cluster-cup” stage, and in many species is the only stage known.
They are thick-walled, and the contents resemble those of the cluster-cup spores described above.