Characteristic 9

 Shrub with flattened twigs fasciation, sometimes bent  (Attention, see exception 9b)

9a Leaves weakly hairy underneath, often only at the veins; leaves long shoot 7-22 cm L, 1.5-3.2 cm W; petiole 9-12 mm; leaves shortlot 3.3-14.2 cm L 5-20 mm W; leaf margin weakly toothed and slightly rolled over; petiole with gutter at the top; most petioles also rose-coloured with that colour continuing into the main vein; leaves shiny green at the top, blue-green at the bottom; male plants; leaves rarely attacked (leaf miners, rust, etc. ). 

► Salix udensis 'Sekka' (syn. S. sachalinensis cv. 'Sekka') 

9b Leaves identical to previous taxon, but without fasciation formation! Young sap-rich twigs turn strikingly pink after debarking. 

► Salix udensis 'Kioryu'

9c Leaf long shoot very broad, 4-16 cm L, 1-6 cm W; short shoot 3.5-9.5 cm L, 1-3.6 cm W; petiole 9-12 mm; wedge-shaped leaf base; leaf tip sharp, often slightly twisted; leaf margin smooth and sometimes slightly rolled downwards; a few glandular tips; widest leaf width short shoot upper half, on long shoot in the middle; upper petiole longle often pinkish, with gutter at top; leaf blade bare on top, hairy underneath but not felty or downy; leaf colour above glossy dark green, grey-green underneath; central vein white, upper side sometimes pinkish red; stipules soon falling off; young twigs sparsely hairy, bright green and often red on sunny side; older twigs bare, olive-green to grey-brown. 

'A willow with the leaf length of udensis and the leaf width of caprea'

► Salix caprea x S. udensis 'Sekka' 

9d Leaf long shoot 2.5-11 cm L, 1-4 cm W; short shoot 1.6-9.5 cm L, 1-3.1 cm W; greatest width in upper half of leaf; apex blunt, at lower leaves, apex pointed and often with twisted apex; leaf base wedge-shaped in short shoot and rounded to wedge-shaped in long shoot; leaf margin smooth or crenate at apex and often strongly wavy; petiole 2-18 mm L short shoot, 5-22 mm L long shoot; upper petiole long shoot often with pink hue and gutter; leaf upper surface glabrous, lower surface rather hairy but not felty or downy; leaf colour above matt dark green to somewhat glossy, lower surface grey-green; central vein greenish-white, no pink discolouration; stipules ear-shaped-oval-crenate but soon falling off; young twigs downy-hairy, pale green; older twigs olive-green-brown and often still somewhat felty. 

► Salix cinerea ssp. cinerea x S. udensis 'Sekka'

Note: Sometimes fasciation can occur due to viral infection and is not a hybrid.

Crosses with udensis 'Sekka' always have a red glow in the buds.

9e Leaf long shoot very long, 10-23 cm L, 1.8-4.3 cm W; short shoot 3.5-12 cm L, 1-1.9 cm W; greatest width about in the middle; apex pointed; leaf base wedge-shaped; leaf margin entire and sometimes slightly rolled downwards, a few glandular tips; petiole from 6 mm L short shoot to 30 mm L long shoot; upper surface of long shoot often with pink tinge and gutter; leaf upper surface glabrous, lower surface hairy but not felty or downy; leaf colour upper surface glossy dark green, lower surface grey-green; central vein white, upper surface sometimes pinkish-red; stipules ear-shaped-ovate serrated but soon falling off; young twigs sparsely hairy, bright green; older twigs glabrous and greyish-olive green; leaves often attacked (leaf miners, rust, etc.) unlike S. udensis cv. 'Sekka'. 

► Salix udensis 'Sekka' x S. viminalis