Heliconia

Nice series. The heliconia are some of the hardest plants to identify to species level, even for botanical gardens because of the many cultivars! As far as I know there are no wagneriana's with leaves that have a purple mid rib. I think that the speciman in your photo is the Heliconia stricta. The speciman plant here looks like it doesn't have enough light and it's growth is stunted but it carries all the hallmarks of a stricta, 3 - 5' tall, 4 to 6 bracts that are mostly red with a narrow green and yellow lip, red rachis, sepals that are green distally with white tips and white below, and the hallmark purple/marroon midrib with slightly undulated leaf edges.