  We report the discovery by the intermediate Palomar Transient Factory (iPTF)
of a candidate tidal disruption event (TDE) iPTF16axa at $z=0.108$, and present
its broadband photometric and spectroscopic evolution from 3 months of
follow-up observations with ground-based telescopes and Swift. The light curve
is well fitted with a $t^{-5/3}$ decay, and we constrain the rise-time to peak
to be $<$49 rest-frame days after disruption, which is roughly consistent with
the fallback timescale expected for the $\sim 5\times$10$^{6}$ $M_\odot$ black
hole inferred from the stellar velocity dispersion of the host galaxy. The UV
and optical spectral energy distribution (SED) is well described by a constant
blackbody temperature of T$\sim$ 3$\times$10$^4$ K over the monitoring period,
with an observed peak luminosity of 1.1$\times$10$^{44}$ erg s$^{-1}$. The
optical spectra are characterized by a strong blue continuum and broad HeII and
H$\alpha$ lines characteristic of TDEs. We compare the photometric and
spectroscopic signatures of iPTF16axa with 11 TDE candidates in the literature
with well-sampled optical light curves. Based on a single-temperature fit to
the optical and near-UV photometry, most of these TDE candidates have peak
luminosities confined between log(L [erg s$^{-1}$]) = 43.4-44.4, with constant
temperatures of a few $\times 10^{4}$ K during their power-law declines,
implying blackbody radii on the order of ten times the tidal disruption radius,
that decrease monotonically with time. For TDE candidates with hydrogen and
helium emission, the high helium-to-hydrogen ratios suggest that the emission
arises from high-density gas, where nebular arguments break down. We find no
correlation between the peak luminosity and the black hole mass, contrary to
the expectations for TDEs to have $\dot{M} \propto M_{\rm BH}^{-1/2}$.
