Melanthera nivea

(Melanthera means “black anthers,” and nivea means “snow”)

Asteraceae

SQS by John Bradford

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Around here I tend to think of Snow Squarestem as a modest, attractive little native wildflower encountered occasionally trailside in moist areas.  But in some ways it looms a little larger.  The plants likes disturbance, and my encounter with it yesterday was along a wetland trail with the marginal soil torn asunder by feral hogs, which seemed to favor the plant. It comes up from the soil seedbank when the hogs or other disturbers disturb. I wonder how long the seeds (achenes) can sleep awaiting their moment.

By JB

Why think it rises from disturbed seedbanks?   There are places in Southern Mexico where slash and burn agriculture is practiced.  Farmers cut forest, burn the residue, grow crops over a limited period, and then move on.    Looking at post-abandonment recovery of such sites, ecologist Jorge Meave and others found Snow Squarestem to be the most abundant re-invader.  

To go from unsurprising to weird, in Nicaragua biologist Hilary Erlener and collaborators reported (in Pan-Pacific Entomologist Vol 92 2016) a species of ground-nesting bee to live adjacent to an active volcanic vent spewing poison gas and nasty ash.    The only plant nearby on the volcano, and feeding the hotfooted bee was Snow Squarestem.

Rising opportunistically from churned soil from the Central U.S. to Brazil,  you might say Snow Squarestem is a mighty colonizer, despite its humble aspect.  Mighty colonizers must make a ton of seeds to deposit in the seedbank.  Some weeds, such as Dandelion, do that by skipping pollination altogether. But maybe a “more textbook”  approach is to be very good at getting pollinated, as pollination spawns seeds—whether in Kentucky, Mexico, or Guyana.   That wide range of places might imply “welcoming” a corresponding wide range of pollinators.   Seems true.  Below are those I managed to snap standing like paparazzi a few minutes yesterday by a clump (and that was merely one clump in  one place at one time,  and I missed some).   The plant most certainly entertains all visitors.

Yesterday: