I wish folks wouldn't use the name "Osborne Prolific" (Osborn Prolific) as it applies to two different cultivars! Here is what Condit listed in his 1955 "Fig Varieties: A Monograph":
Osborn = Archipel, 414
Osborn Prolific (Rust) (C), 420
Osborn’s Prolific = Archipel, 414
It would help to know which variety people are talking about when they say "Osborne Prolific" (Osborn Prolific)!
kiwibob, Seattle