abundance African wood-sorrel Bermuda-buttercup Bermuda-sorrel buttercup-oxalis Cape-cowslip Cape-sorrel cotyledon English-weed goat's-foot groud-cover invasive noxious-weed oxalis oxalis-pes-caprae reflections sorrel sourgrass soursob soursop trifoliate-leaves tristylous-flowering-plant weed weeds wood-sorrel yellow-sorrel flora flowering flowers yellow