I, too, doodled a do.
I find it perfectly reasonable that plump helmets would be an average mushroom which develops a very succulent bloom in order to generate and spread it's spore, as well as for storage of food and water, where the fungus is incapable of digging into the rocky cavern floor.
Pig tails use rigid spiral structures to elevate their spores above the cavern muck. The sticky spores exist on the outside of the fungus' cap, where they hopefully rub off on passing animals, spreading them quite a ways. The stalks grow in the way they do so that the fungus is not crushed by the animal, and I actually imagine them as looking more like a hemispherical brain coral, composed of a great multitude of these stocks twisted together. The stalks are fibrous and make good cloth. I just suck at MSpaint and spiral patterns.
Cave wheat elevates it's tiny spore caps on very thin, wispy stalks, making it look like a field of surface grass. The incredibly small, hard spores spread by being ingested by animal life.
Sweet pods, like cave wheat, spread their spores via elevated stalks, but instead of developing a vast quantity of cheap spores, they develop a few high-potency offspring which grow in a ring around the bulbous pod at the end. The pod, as I depicted it, is actually a hollow cavity wherein a colony of bacteria is grown in symbiosis with the fungus; the fungus provides nutrients and an immune system to deal with threats to it's bacterial colony, which develops mostly in the base of the fungus, whilst the colony produces a huge quantity of simple sugars, which animals love, and are bright red-gold bio-luminescent organisms, which, thanks to thin membranes on the exterior of the pods, are highly visible to any animal which still has eyes, which I wager makes a good incentive for animals in the underdark of dwarf fortress to still have functioning eyes where earthly organisms in caves often lose them; bio-luminescent bacterial colonies and fungi that break down decaying organic matter and process mineral resources provide a basis of the food chain, and organisms that can still see them, and thus quickly locate and ingest them, are more successful than organisms which cannot, so animals like elk birds, dralthas, and rutherers use their eyes to locate these food sources. In my image, the sweet pod is developing a second stalk, which when ripe will begin to fill with bacteria, producing sugar and glowing brightly.
Quarry bushes are a fungi which spread best via their creeping vines, which form nice bushy thickets, the roots penetrating rocks to allow them to make the most of every surface of the caverns. The "leaves" are starchy, long-term storage vessels.
Dimple cups are small, toxic fungi that grow low on the cavern floor.
Cavern moss and floor fungi would probably be all manner of other, much smaller bacteria and fungi which develop throughout the caverns.