 Why did Callahan think Trillium was Berta when he first spotted her?
At the first flash of red on the bank of meters Apprentice Burnerman O'Rielly had slammed the safety helmet on his head; he was already throwing open the lock to the burner room. A dozen burners on this ship; why did something crazy have to happen to O'Rielly's? Ever since Venus blast-off O'Rielly had been in Four's watch room. Well, ma'am, O'Rielly searched every cranny where even a three-tailed mouse of Venus could have stowed away. Somehow he doubted that Burner Chief Terrence Callahan's mood, or Captain Millicent Hatwoody's, would be improved by knowledge of she who was in O'Rielly's shower now.
 Because Berta was Trillium's Grandmamma and she resembled her from a hundred and twenty-five years ago.
 Because Berta was Trillium's Grandmamma and she resembled her from a hundred and twenty-five years ago.  Because she introduced herself as so and led him to believe that was who she was.  Because all the Venus women have the same enchanting appearance.  Because only Berta was able to enter the ship.