Hi ontarioice & welcome to the fun & games of ' the Generalist' this is my fourth try & it's still a challenge [& always will be I think]
Rampton is right for 37d, I have Acanthaceae for 45a & endogen for 47a if this is any help.
I've put Sterno in for 19A - when you have all or most of the letters in the yellow blocks write them down & you'll have enough probably to make a word, tie it in to 15a & go from there - hope that helps, I know the last one like this Kazizere took me by the hand [on cyberlink] & helped me through it, for which I am forever grateful, so good luck - Steff