In article , P van
Rijckevorsel writes
Martin Rand schreef
Let's hear it for the Atkinson Discriminant Function! :-)

+ + +
I assume that is a way to learn Russian quickly?
PvR

ADF=12 LTF + 2 DFT + 2 LTW - 23

(take the mean of 5 leaves from short-shoots)

LTF (Leaf Tooth Factor) - # of teeth projecting beyond line connecting
tips of main teeth at ends of 3rd and 4th lateral veins, subtracted from
the total number of teeth between these 2 main teeth.

LTW (Leaf Tip Width) - width in mm of leaf 1/4 distance from apex to
base.

DFT (Distance to First Tooth) - distance in mm from apex of petiole to
first tooth.

Positive values of ADF are B. pendula; negative values are B. pubescens.
Error rate 7%. Most errors are B. pubescens with slight positive values.

(Description taken from Stace.)
--
Stewart Robert Hinsley