differences in flower shape. im not sure of technical terms but anyone who has a blooming or has looked closely at a blooming sandersonii should be able to figure out what im talking about.
"typical form": tall skinny "ears"(jackrabbit type), the "skirt" is narrower than the "blue form" forming maybe a 50-60 degree angle, and the "spur" curves from where it connects to the base of the flower out and past the bottom of the "skirt" for quite a distance(maybe half the "spurs" length) touching the bottom of the "skirt" in most flowers.
"blue form": short squat "ears"(cottontail type), "skirt" flares more than the typical(maybe 100-110 degrees). the "spur", from the base of the flower, starts to curve but after a short distance starts heading in a downward direction and does not protrude past the bottom of the "skirt", never coming even close to touching the skirt.
after a closer inspection, i found some flower stalks on the "blue form" that have 3 flowers but the entire stalk is still only an inch or a lil more tall. the "typical form" sometimes has 5 or 6 flowers per stalk but these stalks are up to about 5.5 inches tall. the flower stalks of the "typical form" that only have 3 flowers(the max found on my "blue form" so far) are still twice the length of the same 3-flower stalks on my "blue form". total flowers on in my "blue form" pot numbered 16 before a couple were sacrificed for close comparison to the typical form. didnt notice any great diferences in lolon shape but this species seems to produce slightly different shaped lolons depending on age, light, ect so its kind of difficult to compare them.