Trachelium caeruleum L.
Diagnostic description:
A simple or branched, woody-based herbaceous perennial to 90 cm tall. Leaves ovate or lanceolate, with doubly serrated margins. Flowers blue-lilac, in an umbel-like, dense terminal cluster up to 10 cm across. Corolla 6 mm to 8 mm long, tubular, with 5 very small lobes.
Distribution:
Local: Fairly common in Gibraltar. Found in scattered places especially on walls around the town area.
Global: Found along the west Mediterranean region and the Iberian peninsula.
Ecology:
Flowers between May, June and July (September).
Habitat:
Grows on old walls and from limestone crevices, especially if damp.