I'd guess 'Hawaiian Punch'. It has a glossy upper leaf surface and more red in the veins on the underside. That matches the USPP description as well (PP24,596).
I've never grown 'Rhubarb' and not been able to find a consistent description. Photos here show it with a matte upper leaf surface.
http://www.briansbotanicals.ne... This also shows only the mid and basal ribs colored red on the underside.
http://www.plantdelights.com/C...
https://www.agristarts.com/ind... I believe 'Red Stem' = 'Rhubarb'
'Pink China' Also has a matte surface.
http://www.briansbotanicals.ne...
