Bartrum has his mother as unknown, giving this note:
"For the grouping under mothers see LD.H. 10, RV 295. The groups may be correct, but the mothers are wrongly given by RV. Llywarch and Cadwgon had the same mother. Pen 126 pp. 8, 15, LD. H. 10 and perhaps G 106. Cf. C 85."