Yup that's the same plant I have pictured in my photo above. I grow it in very hard water in sand with manure under the sand. It does well with lots of fertilizer and either low or high light. In higher light the leaves are smaller and dark becoming tiger striped and bronze under very high light. Under lower light they're green and in medium light they're green with brown edges.
It sends out VERY long runners. It'll sit there for months apparantly doing nothing then one day you'll notice there are tiny plants all over the tank. One plant will completely colonize a 35 gallon tank in about a year.
I'm not *certain* it's undulata. That's just my best guess. I'll stick some outside this summer - that usually gets things to flower then we'll know for sure.
I've had this plant for over 10 years. I got it from Charlie Drew who got it from some guy in the states who called it "C. versicolor" (there is no such species).
Here it is under high light:
http://images.aquaria.net/plants/Cry...D/DSCF0001.jpg
Under low light:
http://images.aquaria.net/plants/Cry...ND/Image19.jpg
10 years ago:
http://images.aquaria.net/plants/Cry...ND/Image80.jpg
Looking at all my pics:
http://images.aquaria.net/plants/Cryptocoryne/u/UND/
I notice that growth was much much stronger a decade ago (image80 above).
I got the "manure under the sand" trick from Charlie for got it from Ma Reimer. Charlie said the manure is only good for 10 years so I guess it's time to tear that tank down and renew it.
It seemed to do really well with a LOT of Endlers livebearers in the tank:
http://images.aquaria.net/fish/liveb...03/image14.jpg
Yours may not have enough space. It really likes to spread out.