Palm trees are highly visible and arguably iconic in the Los Angeles landscape. Interestingly, the number of palm species offered in
time period 1900–1929 was significantly greater than the number
of species offered in time period 1930–1959. However, there was no
statistically significant difference in the number of species offered
in time periods 1930–1959, 1960–1989, and 1990–2011. An overall
quadratic trend was observed with time (p < 0.05)