In the
unknown species seen here, the spur coils round. This
tendency is seen to an even greater extent in D.
bulleyanum, a species from China in which the spur
coils like a ram's horn. In quite a few species, the spur points upwards or curves upwards. How is the nectar retained in such spurs? More often, the spur curves downwards.
In D.
cashmerianum the spur is inflated so that the flower
looks more like an aconitum than a delphinium. This is
probably an adaptation related to the climate of the high
mountain region in which it grows, not an indication that
it is closely related to aconitums. This species is also unusual in having the flowers arranged in a cluster or corymb at the top of the stalk rather than having florets distributed along a stem to form a spike.
In the
dwarf cultivar 'Blue Mirror' which is a form of D.
grandiflorum var chinense, the spur is absent. The
flower then looks like a blue 'Buttercup'. Notice that
these flowers also lack petals. The complete absence of a spur is very unusual in delphiniums but some species have only short spurs.