delphinium
Concise Oxford English Dictionary © 2008 Oxford University Press:
delphinium /dɛlˈfɪnɪəm/
▶noun (pl. delphiniums) a popular garden plant bearing tall spikes of blue flowers. [Genus Delphinium.]
– origin mod. L., from Gk delphinion ‘larkspur’, from delphin ‘dolphin’ (because of the shape of the spur, thought to resemble a dolphin's back).
'delphinium' also found in these Oxford entries:

