The top find for me had to be Pale Pink-sorrel (Oxalis incarnata), as I had not come across this before. A few plants of this introduced annual were found by the riverside path in Boston Spa.
Thorp Arch churchyard provided the yellow-flowered form of Gladdon or (rather unfairly) Stinking Iris (Iris foetidissima var. citrina)
Several locations provided Lesser Burdock (Arctium minus ssp. pubens). This subspecies is thought to be of hybrid origin and it is relatively widespread in VC64 despite the general absence of one of its putative parents - Greater Burdock (Arctium lappa).
I then took a trip over to Thorp Arch Trading Estate where I knew there were some small relict areas of species-rich calcareous grassland. This proved well worth the trip with the grassland in peak bloom.
Some of the plants seen include Dark Mullein (Verbascum nigrum), Tutsan (Hypericum androsaemum) and Clustered Bellflower (Campanula glomerata).