monophyllous
/məˈnɒfɪləs/ /ˌmɑnə(ʊ)ˈfɪləs/Botany
adjective
1Of a plant: having a single leaf or leaflet. Also (of a tree's canopy): consisting of a single layer of leaves. Now rare.
2Of a foliose lichen: having a thallus with a single leaflike lobe.
Origin
Mid 18th century (in an earlier sense). From mono- + -phyllous.