marcescent
adj.
5L marcescens, prp. of marcescere, to wither, decay < marcere, to wither < IE *merk3, to grow soft, rot < base *mer3, to rub > MARE36 Bot. withering but not falling off

Excellent. We have a mallus that suffered from fireblight last year. Now I have a word to describe the appearence of its leaves. Thanks Dr Bill.

http://www.capitalnursery.com/pdf/fireblight.pdf