The simplest of these Polyporacece is the dry-rot fungus, Merulius lacrymans. The food-seeking portion consists of fine white threads, mycelium, which penetrate the woodwork of buildings, causing it to crumble to dust. The fruiting portion consists of flat, irregular bodies whose under surface bears the spores in shallow pits separated by narrow ridges. Water is excreted from these flat disks, which, from the habit of dropping like tears, has suggested the specific name lacrymans, from the Latin lacrymare, to weep.