It's a C chromatic, straight up. Al the slide jabs work, and the line lies nicely in E, not usually exactly the grooviest key on the chromatic.
You could do it on an A, but you don't get that nice slide jab into the 3rd and the 3rd (G#) and 6th (C#) of the scale, which is one of the joys of playing it on a C
THIS is what I was tellng you the other day off list. Glissing into a note, catch the very start of said note (most likely a natural) and QUICKLY chipping or clipping the note away as you settle onto a sharp. This is a so-called trademark of Steveland's playing.
--- Russegr9, notice Winslow's statement above, re: "slide jabs". Notice also the word (or symbol) #.