Appendix 2 'Reddish hairs'

Comparing willows with russet hairs 

!!!  Sometimes confusion can be caused by the presence of a reddish fungus on the underside of the leaf. This is difficult to see with a magnifying glass but obvious when using a bino (x 50).

The veins (not the hairs) can also colour the underside of the leaf a little red.

In principle, all hybrids with an S. cinerea parent can have reddish hairs on the underside of leaves. Hereafter the most special ones. 

Salix cinerea ssp. oleifolia (syn. Salix atrocinerea) :

Striae 5-30-(60) mm L; mature leaves top glossy dark green; flat or rarely wrinkled, leaf tip not pointed and rarely twisted; underside with predominantly rust-brown hairs and conspicuous russet veins; leaf shape elliptical ovate, inverted ovate; short-leaved 4.5-7 cm L, 15-26 mm W; long-leaved up to 11.5 cm L, up to 4 cm W; usually at least 2x as long as wide; conspicuous and persistent buttress leaves; twigs weakly to strongly hairy and more reddish than Salix cinerea ssp. cinerea. 

Salix x charrieri (S. aurita x S. cinerea ssp. oleifolia) :

Top leaves often twisted. Short-leaved 3-5 cm L. Reddish hairs on veins underside. Striae frequent and variable 5-25 mm L. 

Salix x guinieri (S. cinerea x S. cinerea ssp. oleifolia): 

Support leaf absent, or falling off early, except on fast-growing young twigs. Rosy hairs scattered between majority grey hairs underside of leaves. Branches intermediately hairy, balding seasonally. Striae 4-47 mm L. 

Salix x quercifolia (S. caprea x S. cinerea ssp. oleifolia) 

Similar to S. x reichardtii but usually not such a vigorous shrub. Rosy hairs on underside of leaves.  Top leaf often twisted.

(Note Meikle: russet hair is not always inherited .)