  We report the magnetization, ac susceptibility, and specific heat of
optically float-zoned single crystals of CePdAl$_{3}$. In comparison to the
properties of polycrystalline CePdAl$_{3}$ reported in the literature, which
displays a tetragonal crystal structure and no long-range magnetic order, our
single crystals exhibit an orthorhombic structure ($Cmcm$) and order
antiferromagnetically below a N\'eel temperature $T_{\rm N}$ = 5.6 K. The
specific heat at zero-field shows a clear $\lambda$-type anomaly with a broad
shoulder at $T_{\rm N}$. A conservative estimate of the Sommerfeld coefficient
of the electronic specific heat, $\gamma = 121~\mathrm{mJ~K^{-2}~mol^{-1}}$,
indicates a moderately enhanced heavy-fermion ground state. A twin
microstructure evolves in the family of planes spanned by the basal plane
lattice vectors $a_{\rm o}$ and $c_{\rm o}$, with the magnetic hard axis
$b_{\rm o}$ common to all twins. The antiferromagnetic state is characterized
by a strong magnetic anisotropy and a spin-flop transition induced under
magnetic field along the easy direction, resulting in a complex magnetic phase
diagram. Taken together our results reveal a high sensitivity of the magnetic
and electronic properties of CePdAl$_{3}$ to its structural modifications.
