Does the name start loo or lyoo?
heard as lyoocobryum
spelled leucobryum
Most speakers say loo, and lyoocobryum is written leucobryum either way.
What the ear did
The letters eu are the problem, not the speaker. They say yoo in eucalyptus, Europe and eulogy, and oo in leucocyte, leukaemia and this genus. There is no rule that predicts which, only the individual word.
L-E-U-C-O-B-R-Y-U-M
The full entry for leucobryum covers the name itself.