Fouquieria is a genus of desert plants in the family Fouquieriaceae including the ocotillo and the boojum tree. They have succulent stems with thinner spikes projecting from them, with leaves on the spikes. They are unrelated to cacti and do not look much like them; their stems are proportionately thinner than cactus stems and their leaves are larger.
... touches the x-axis in a single point.)
If the discriminant is positive, then there are two different solutions x, both of which are real. (Geometrically, this means ...