A Crinum zeylanicum L. x Crinum Macleayi hybrid.  The latter is unidentified but is probably a form of one of the native Australian species, Crinum flaccidum Herb. or Crinum pedunculatum R.Br.

In 1845 and 1846 William Macarthur described ten Crinum scabro-macleayii hybrids in his gardening notebooks.  [MP A2948 Notebook no.4, p.4].

No.4.  Leaves long, narrower, pointed, deep green gradually tapering from the base, 2½ inches, to a slender point, 12-14 inches.  A number are almost recumbent.  Scape 2 feet.  [The next section is somewhat indistinct, but does describe a scape with 12-16 fragrant flowers.]  The petals are ¾-1 inch broad, 3 inches long, the corolla expanding to 4½ inches diameter, of delicate rosy pink inside and out but white at the base and with an irregular broad crimson stripe in the centre, very fragrant.  [The next section is also indistinct] Filaments white, scabrous, anthers white, stigma tipped with purplish crimson.