hyperbolas are never a waste of time

i can’t stop looking at the gentle hyperbolas created at the base of these leaflets where they meet the stem, specially that top leaf. i found these two in my plant press. it took me hours of googling to identify them. i din’t know this pair was part of  a compound leaf. so i had started my search with  “simple toothed ovate leaves” and “simple toothed elliptical leaves”.  i found elm, apple, birch and rose leaves. all very very similar to my pair here..but no hyperbolas. i was just about to give up when i finally found a tiny infographic of  leaf types that happened to include ash. ash! would i consider those hours a waste of time? no way. i will forever know an ash leaf when i see it. it’s the only one with hyperbolas. and not a single field guide mentions that in their description of ash. weird.

pressed twig with two black ash leaflets