  Lenticular galaxies are notoriously misclassified as elliptical galaxies and,
as such, a (disc inclination)-dependent correction for dust is often not
applied to the magnitudes of dusty lenticular galaxies. This results in overly
red galaxy colours, impacting their distribution in the colour-magnitude
diagram. It is revealed how this has led to an underpopulation of the `green
valley' by hiding a `green mountain' of massive dust-rich lenticular galaxies -
known to be built from gas-rich major mergers - within the `red sequence' of
colour-(stellar mass) diagrams. Correcting for dust, a `green mountain' appears
at $M_{\rm *,gal}\sim10^{11}$ M$_\odot$, along with signs of an extension to
lower masses producing a `green range' or `green ridge' on the green side of
the `red sequence' and `blue cloud.' The `red sequence' is shown to be
comprised of two components: a red plateau defined by elliptical galaxies with
a near-constant colour and by lower-mass dust-poor lenticular galaxies, which
are mostly a primordial population but may include faded/transformed spiral
galaxies. The quasi-triangular-shaped galaxy evolution sequence, previously
called the `Triangal', is revealed in the galaxy colour-(stellar mass) diagram.
It tracks the speciation of galaxies and their associated migration through the
diagram. The connection of the `Triangal' to previous galaxy morphology
sequences (Fork, Trident, Comb) is also shown herein. Finally, the
colour-(black hole mass) diagram is revisited, revealing how the dust
correction generates a blue-green sequence for the spiral $and$ dust-rich
lenticular galaxies that is offset from a green-red sequence defined by the
dust-poor lenticular and elliptical galaxies.
