Be aware that there are TWO Peter Taylor Monographs on Utricularia.
The first is a short (about 100 pages) document that covers a limited
distribution of Utrics (mainly Africa if memory serves me). The second
is several hundred pages and covers all known Utrics, including
Polypompholyx (now reclassified as Utrics by Taylor).
The first book should cost in the region of #20 The new (about 1-2
years old) book costs #40 (that is today's price in the UK ex-postage).
Regards
Paul