Sentence:  Bolwes, <WSD>"loggerheads</WSD>", "centaurea nigra." ... Bolwes is "balls", the hard round heads of the wort. <WSD>Loggerheads</WSD> is a name I have often heard in Oxfordshire. 
Meaning of the word marked with <WSD> tags:  A thistle-like flowering plant of the genus "Centaurea", particularly the (common knapweed) ((ver=181128)).