What is eating my pussytoes? I don’t mind sharing, but for a good cause.

You’ve got a winner! The caterpillar on your pussytoes is that of the pink, black, white and orange American painted lady butterfly. Recently declared the longest-migrating butterfly on the planet, it flies even farther than the famous monarchs. Found around the world, their longest migration occurs from Africa — crossing the Sahara — to Europe and back. Most achieve this in a relay of generations, yet some extraordinary ones make it from Europe to Africa alone. Unsurprisingly, the caterpillars need to seriously fuel up, increasing up to 1,000 times in weight. In Maryland, they relish marigolds, butterfly weed, goldenrod and the weeds dogbane and vetch. Pussytoes, another favorite food, is a native ground cover gaining in popularity. Our several species can grow in wildly poor soil, have fuzzy white flowers like, well, pussytoes and are deer-resistant.

When my white dog goes outside lately, he comes back in with a black dust-like substance on his paws. Now I’ve noticed the same black stuff on my toes when I wear flip-flops and walk on the grass. Is this pollen? My dog licks his feet. I can’t see where this black stuff comes from.

This sounds like the fungal spore masses of slime mold. It’s not as bad as it sounds. Slime molds grow when conditions provide just the right amount of warmth and humidity. Though the spore masses cling to grass blades, slime mold is not a parasite of grass. It gets nourishment from micro-organisms such as other fungi and bacteria in the soil and thatch. Spore masses can be white, gray, brown, purple or black. When young, they are sticky to the touch, but quickly dry and then easily rub off. We've not heard it is a problem for animals, but you can check with your vet.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Maryland’s Gardening Experts” to send questions and photos.