This is from Mathematica v9.What version are you using? Perhaps a bug? :)
Inv = WeierstrassInvariants[{1, I/3}];
Plot[Re[N[WeierstrassP[2*x + 1 + I/3, Inv], 100]], {x, 0, 1/2}, WorkingPrecision -> 100]
This is from Mathematica v9.What version are you using? Perhaps a bug? :)
Inv = WeierstrassInvariants[{1, I/3}];
Plot[Re[N[WeierstrassP[2*x + 1 + I/3, Inv], 100]], {x, 0, 1/2}, WorkingPrecision -> 100]