This plant I was told was a shamrock, but as I researched clover and such, none had the shape and characteristics of mine. It is trefoil, but shaped as three triangles, open and leaning to sunlight by window, and closed up like little umbrellas by night. Only one trefoil per stem which is about 7 inches long. Root system is a little blob, like a tiny pine-cone shape. It is very hardy! I have included fotos.
I believe it is Oxalis regnellii. Examples follow: http://www.wheatoncollege.edu/academic/academicdept/biology/greenhouse/Photos/oxalis_regnellii.jpg http://www.arhomeandgarden.org/plantoftheweek/articles/shamrock.htm
I'm glad I stumbled across this post! I have what appears to be the same plant-- squared-off leaves that fold down at night, delicate white flowers-- but the tag that came with it has the wrong species name (Oxalis acetosella), so it's been hard for me to find information about it. Thanks a bunch!
