The Collaborative International Dictionary
Perfoliate
Perfoliate \Per*fo"li*ate\, a. [Pref. per- + L. folium leaf.]
(Bot.) Having the basal part produced around the stem; -- said of leaves which the stem apparently passes directory through.
(Zo["o]l.) Surrounded by a circle of hairs, or projections of any kind.
Wiktionary
perfoliate
a. (context botany of leaves English) Appearing to have the stem passing through the blade.
WordNet
perfoliate
adj. of a leaf having the base united around (and apparently pierced by) the stem