Well this turned out to be far more complicated than I had thought!
It seems that ‘in the trade’ A. hemsleyanum and volubile are ‘confused’. They should be distinct, but almost all the plants are hemsleyanum whatever they are called.
Also in cultivation [at least at some time] are a variety of other climbing or at least scandent species.
Aconitum bulbilliferum is sold by Crug with a dusky/reddish flower. The flora says it is blue.
Also to be found, in catalogues at least, have been A.episcopale, finetianum, fischeri var arcuatum and sczukinii.
As far as I can see the flower colour and form are hugely variable within each species.
‘Red Wine’ has been assumed to be a hybrid because it came from botanic garden seed [rather than wild collected] and doesn’t match any recorded species. That it breeds true with very little variation doesn’t rule out hybridity, but it would be uncommon for a primary hybrid. If it could be found in the wild I think it would be described as a new species.
Just for the record from the
e-flora for China, Aconitum hemsleyanum;
Caudex conical, ellipsoid-globose, or fusiform, 1.6--10 cm, to 1.6--2.8 cm in diam. Stem usually purplish, twining, branched, glabrous. Leaves long petiolate; petiole 4--10 cm, sparsely pubescent or nearly glabrous; leaf blade pentagonal or ovate-pentagonal, 6.5--12 × 8--13 cm, glabrous, base cordate or subtruncate, 3-parted; central lobe trapezoid-rhombic or ovate-rhombic; lateral lobes obliquely flabellate, unequally 2-lobed. Inflorescence terminal, 2--6(--12)-flowered; rachis and pedicels glabrous or appressed pubescent, or pedicels spreading pubescent; proximal bracts leaflike or broadly elliptic; distal bracts linear, smaller. Pedicels usually pendulous, 2.2--6 cm, with 2 bracteoles proximally or distally; bracteoles linear, 3--5 × ca. 0.5 mm, glabrous or pubescent. Sepals dark blue, abaxially glabrous or sparsely pubescent, or both surfaces pubescent; lower sepals 1.2--1.3 cm; lateral sepals suborbicular, 1.5--1.6 cm; upper sepal high galeate or cylindric-galeate, 2--2.4 cm high, clawed or indistinctly so, lower margin erect or slightly concave, 1.7--1.8 cm. Petals glabrous, or petaline lip and claw sparsely pubescent; limb ca. 1 cm × 4 mm; lip ca. 5 mm; spur incurved or circinate, 2--8 mm. Stamens glabrous; filaments 2-denticulate or entire. Carpels 5, glabrous or rarely ovary pubescent. Follicles erect, 1.2--1.5 mm; persistent style 2.5--5.5 mm. Seeds ca. 3 mm. Fl. Aug--Oct.
Aconitum volubile;
Caudex unknown. Stem twining, branched, glabrous or apically sparsely retrorse pubescent. Middle cauline leaves long petiolate; petiole 3.5--6 cm; leaf blade pentagonal, 7--9 × 8--10 cm, papery, abaxially glabrous or nearly so, adaxially sparsely appressed pubescent, base cordate, 3-sect; central segment usually stipitate, rhombic-ovate; lateral segments obliquely flabellate, unequally 2-fid or nearly to base. Inflorescence terminal or axillary, 3--5-flowered; rachis and pedicels densely spreading yellowish pubescent, or retrorse and appressed pubescent; basal bracts 3-fid, others linear. Pedicels 2--3.8 cm, with 2 bracteoles above middle; bracteoles linear, 2--3 mm. Sepals blue-purple, abaxially spreading pubescent, or retrorse and appressed pubescent; lower sepals 0.8--1.3 cm; lateral sepals 1--1.5 cm; upper sepal high galeate, 1.8--2.7 cm, 1--1.5 cm from base to beak, lower margin oblique upward. Petals glabrous; limb 6--10 mm; lip 3--6 mm; spur incurved, 1.5--3 mm. Stamens glabrous; filaments entire. Carpels 5, glabrous or ovary spreading pubescent. Follicles 1.5--1.7 cm. Seeds ca. 2.5 mm. Fl. Aug--Sep. 2n = 16*.
If anyone can spot an obvious and not overlapping criterion for separation please highlight it!
I’ve got that in hemsleyanum the inflorescence is only terminal but in volubile it can be terminal or axial.
Chad.