Yellow Woodsorrel (Oxalis stricta) also known as: Ceratoxalis coloradensis, Oxalis europaea, Oxalis prostrata, Oxalis rupestris, Xanthoxalis florida, Shamrock, Sleeping Beauty, Sour Trefoil, Sour Grass, Common Yellow Oxalis etc.  Division - Magnoliophyta Class - Magnoliopsida Subclass - Rosidae Order - Geraniales Family - Oxalidaceae Genus - Oxalis  I was always told this was a clover, but it isn't. It has a completely different flower than the clovers, though they both belong to the Magnoliopsida class. As far as common garden weeds go, this is a good one. It pulls out easily if you want to get rid of it, but it is a nice looking plant with nice little yellow flowers.   Taxonomic List List by Scientific Name List by Common Name |