Mid 19th century; earliest use found in Alphonso Wood (1810–1881), botanist. From petiolule + -ate. Compare scientific Latin petiolulatus and French pétiolulé (both 1813 or earlier).
Definition of petiolulate in US English:
petiolulate
adjectiveˌpɛtɪˈəʊljʊleɪt
Botany rare
Having a petiolule.
Origin
Mid 19th century; earliest use found in Alphonso Wood (1810–1881), botanist. From petiolule + -ate. Compare scientific Latin petiolulatus and French pétiolulé (both 1813 or earlier).