Clematis 1b Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 1c Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 1e Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 1f Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 1g Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 2a Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 2b Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 3c Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 5b Torndirrup, Albany, Western Australia 110930 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 6a (cult) Stratford NZ 151111 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 6b (cult) Stratford NZ 151111 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 6c (cult) Stratford NZ 151111 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 1 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 2 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 1 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 2 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 3 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 4 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 5 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 6 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 7 Garda de Sus, Romania 090615 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina 8 Lund Bot Garden 130523 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 1 Tretten, Norway 820728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 2 Tretten, Norway 820728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 3 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 4 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 5 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 6 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 7 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis alpina ssp sibirica 8 ENE of Peura, Lappland, Finland 220728 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cf heracleifolia 3 Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cf heracleifolia 4 Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cirrhosa 1 Menetes, Karpathos, Greece 040518 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cirrhosa 2 Menetes, Karpathos, Greece 040518 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis diversifolia 1 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis diversifolia 3 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis florida 1 Lund Bot Garden 160704 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis florida 2 Lund Bot Garden 160704 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis florida 3 Lund Bot Garden 160704 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis foetida 1 Otari Botanical Garden, Wellington NZ 151114 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis foetida 2 Otari Botanical Garden, Wellington NZ 151114 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis foetida 3 Otari Botanical Garden, Wellington NZ 151114 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis foetida 4 Otari Botanical Garden, Wellington NZ 151114 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis forsteri 1 Baring Head SE of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis forsteri 2 Baring Head SE of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis forsteri 3 Baring Head SE of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis forsteri 4 Baring Head SE of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia 1 Copenhagen Bot Garden 120919 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia 2 Copenhagen Bot Garden 120919 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia 3 Copenhagen Bot Garden 120919 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia var davidiana 2 (cult) Brunnby Sk 060801 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia var davidiana 3 (cult) Brunnby Sk 060801 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 10 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 3 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 4 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 5 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 6 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 7 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 9 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima var scottii 1 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis integrifolia 1 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis integrifolia 2 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis integrifolia 3 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 1 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 2 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 3 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 4 Copenhagen Bot Garden 130604 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 5 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis macropetala 6 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis montana 3 Napa Hai, Yunnan 110709 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis paniculata 1 Taranaki (Mt Egmont) NZ 151111 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis paniculata 2 Taranaki (Mt Egmont) NZ 151111 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis paniculata 3 Wainuiomata Forest Reserve E of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis paniculata 4 Wainuiomata Forest Reserve E of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis paniculata 5 Wainuiomata Forest Reserve E of Wellington NZ 151115 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis patens 'Nelly Moser' 1 (cult) Höllviken Sk 100625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis patens 'Nelly Moser' 2 (cult) Höllviken Sk 100625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pauciflora 1 Torrey Pines, San Diego, CA 130418 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pauciflora 2 Torrey Pines, San Diego, CA 130418 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pauciflora 3 Torrey Pines, San Diego, CA 130418 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 10 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 5 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 6 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 7 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 8 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 9 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 2 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 3 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 4 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 6 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 7 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 8 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 4 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 5 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 6 Valea Morii, Romania 090617 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 8 (cult) Höllviken Sk 150718 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 9 (cult) Höllviken Sk 150718 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis stans 1 Lund Bot Garden 080926 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis stans 2 Lund Bot Garden 080926 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 3 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis terniflora var mandshurica 1 Copenhagen Bot Garden 160713 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis terniflora var mandshurica 2 Copenhagen Bot Garden 160713 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis terniflora var mandshurica 3 Copenhagen Bot Garden 160713 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis terniflora var mandshurica 4 Copenhagen Bot Garden 160713 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 1 Höllviken Sk 110820 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 10 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 11 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 12 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 2 Lund Bot Garden 080926 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 3 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 4 Höllviken Sk 110820 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 5 Höllviken Sk 110820 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 6 Höllviken Sk 110820 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 7 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 8 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis viticella 1 NW of Dadia, Thracia, Greece 060606 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis viticella 3 NW of Dadia, Thracia, Greece 060606 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 1a Lund Bot Garden 120907 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 2c Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 3a Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 3b Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 3d Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis 5a Torndirrup, Albany, Western Australia 110930 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 3 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 4 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 5 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis akebioides 6 Shangri-la, Yunnan 110712 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cf heracleifolia 1 Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis cf heracleifolia 2 Copenhagen Bot Garden 130913 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis diversifolia 2 Copenhagen Bot Garden 130625 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis heracleifolia var davidiana 1 (cult) Brunnby Sk 060801 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 1 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 2 Copenhagen Bot Garden 130516 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima 8 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis hirsutissima var scottii 2 Copenhagen Bot Garden 140515 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis ligusticifolia Bergianska, Stockholm 051006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis montana 1 Napa Hai, Yunnan 110709 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis montana 2 Napa Hai, Yunnan 110709 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis ochroleuca 1 Göteborg Bot Garden 130524 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis ochroleuca 2 Göteborg Bot Garden 130524 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis ochroleuca 3 Göteborg Bot Garden 130524 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pauciflora 4 Torrey Pines, San Diego, CA 130418 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 1 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 2 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 3 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis potaninii 4 Lund Bot Garden 121006 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 1 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis pubescens 5 Beedalup Falls Nat Park, Western Australia 110928 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 1 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 2 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 3 Copenhagen Bot Garden 130611 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis recta 7 Valea Morii, Romania 090617 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis stans 3 Lund Bot Garden 120918 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 1 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 2 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 4 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 5 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 6 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis tangutica 7 Dybbölsbro, Copenhagen DK 140922 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis vitalba 9 Lund Sk 130806 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Clematis viticella 2 NW of Dadia, Thracia, Greece 060606 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).