Well, they are mushrooms. And according to George Barron, the author of Mushrooms of Ontario and Eastern Canada, under optimal conditions a Stinkhorn can expand from its nascent "egg" stage to full size within thirty minutes, an impressively fast rate of growth that certainly qualifies as "popping up".
While looking around for something interesting to photograph at the Tweed Heritage Center gardens, I noticed a smell like rotten carrion and wondered if perhaps a hapless mouse or chipmunk had perished and was decomposing in the late season flower beds. This was how I discovered some Ravenel's Stinkhorns (Phallus ravenelii) peeking out of the grass mulch and sawdust. Stinkhorns are often smelled before they are seen, an attribute that some find less than endearing.
Stinkhorns exploit flies, and presumably other insect species attracted to carrion, in a more benign fashion to pass along their genes to the next generation. The sticky, vile smelling sludge at the tip of a Stinkhorn not only contains sugary compounds – a combination of scent and taste that flies find irresistible – it also contains the Stinkhorn's spores, and as the flies crawl around enjoying their dinner the goo sticks to their feet and the insects convey the fungus' spores to new sites.
Unfortunately this specimen is past its peak. The depressions in the morel-like tip are reservoirs for the Skirted Stinkhorn's viscid spore mass, which is long gone, but the fetid scent still lingers on and continues to attract flies. This species of Stinkhorn also sports a doily-like "skirt" around the base of the cap, the frayed remnants of which can be seen in the photos.
With such a limited "best before" date one is lucky to stumble across opportunities to photograph these fascinating fungi, so I was thrilled when a few days later I encountered a colorful group of about a dozen Dog Stinkhorns. Or so I assumed at the time ... having done some more research, I now think these masses of malodorous mushrooms might be Elegant Stinkhorns (Mutinus elegans). The fruitbodies are longer (about 12 to 15 cm in length), there's no distinct separation of the spore mass and stalk, and more of the fruitbody – one third to one half – is covered in slime.
A student of the natural world soon learns that evolution and natural selection proceed according to their own rules, that life adapts as it must in order to survive and perpetuate itself and doesn't care about our human sensibilities ... nonetheless, I was holding my breath whilst taking these photographs.