The Collaborative International Dictionary
Pentadelphous
Pentadelphous \Pen`ta*del"phous\, a. [Penta- + Gr. ? brother.] (Bot.) Having the stamens arranged in five clusters, those of each cluster having their filaments more or less united, as the flowers of the linden.
Wiktionary
pentadelphous
a. (context botany English) Having its stamens fused together at least partly by the filaments so that they form five separate groups, some of which may contain a single stamen.