"Oh, I'll take them through the creatures that most often come up in OWL. Not much left to do - they've studied unicorns and Nifflers, I thought we'd cover Porlocks and Kneazles, make sure they can recognise Crups and Knarls, you know…"
-- Professor Grubbly-Plank during her inspection by Dolores Umbridge (OP15)
Wilhelmina Grubbly-Plank is an elderly witch with closely cropped gray hair and a very prominent chin who teaches Care of Magical Creatures.
Professor Grubbly-Plank was the supply teacher (US: “substitute”) who covered for Hagrid when he was indisposed after Christmas break (January 1995, GF24) and again when he was off negotiating with the giants (OP11).
Grubbly-Plank knew a lot about unicorns and seemed – to Lavender Brown and others of Harry’s year – like a particularly good teacher compared to Hagrid, who had devoted most their class time looking after Skrewts (GF24).
Grubbly-Plank covered classes for Hagrid at the beginning of the 1995-6 school year and also took the first years across the lake (OP10, OP11). She smokes a pipe and uses a monocle. When Hagrid wasn’t available, Professor Grubbly-Plank nursed Hedwig back to health after she was attacked delivering mail to Harry (OP17).
Good with unicorns and owls
Wilhelmina means "a great protector" (feminine of the Dutch/German name "Wilhelm") and grubby means dirty. A good Care of Magical Creatures teacher would be all about protecting animals and not bothered by a bit of dirt either.
From the Web
Writing by J K Rowling on Pottermore: Hogwarts School Subjects
Pottermore feature: Magical Creatures Quiz
Harry Potter Wiki: Wilhelmina Grubbly-Plank