defined by:
L. H. Klotz. Form of the perforation plates in the wide vessels of metaxylem in palm. J. Arnold Arbor., 59(2):105–128, 1978.
Only the interval where the mean of the tribe is comprised is given.
In remark of the state is given the detailed composition with the e v o s t abreviations (extremly oblique, very oblique, oblique, slightly oblique, transverse):
%(e) - %(v) - %(o) - %(s) - %(t)
slope index × 100 = 0 (% tracheids) + 1 (% extremely oblique end walls) + 2 (% very oblique end walls) + 3 (% oblique end walls) + 4 (% slightly oblique end walls) + 5 (% transverse end walls)