Wednesday wildflower: Veronica persica

I've written a few posts about native New Zealand species of Veronica, many of which are hebes.  Lately I've been looking more closely at the introduced species.  There are 16 of these if you regard V. plebeia as native.  One of the commonest is V. persica.

Veronica persica, Kaitoke, Wellington, New Zealand.

It is a common weed in gardens and roadsides.  There are two other common species in similar habitats: V. arvensis and V. serpyllifolia, but these both have much smaller flowers.

Veronica persica flower, Karori, Wellington, New Zealand (scale 1mm)

The flowers have been reported to be pollinated by syrphid flies (hover flies).  A syrphid will fly in to the flower rubbing off pollen from its abdomen onto the protruding stigma.  To hold on while it's feeding, it grasps the bases of the stamen filaments, but these are very narrow at the base and bend like a hinge.  This pulls the anthers into contact with the fly's abdomen, dusting off pollen there.

The native Veronica lilliputiana has creeping stems, tiny greyish leaves, and blue flowers with nectar guides.

Very few native Veronica have such bright blue flowers.  Mostly they're white, sometimes with a touch of blue or mauve.  But V. benthamii in the subantarctic Auckland & Campbell Islands is a good veronica blue, and the tiny creeping V. lilliputiana is also blue, but paler.  A similar thing happens in the forget-me-nots, Myosotis, where most native species have white or yellow flowers, yet two in the subantarctic islands are blue, M. capitata and M. antarctica.  These introduced Veronica also have nectar guides, coloured lines on the corolla lobes, which are thought to attract and guide pollinators.  Again, these are not common in native Veronica, but the speedwell hebe group (about half the former genus Parahebe, e.g., V. lanceolata) have them.  V. lilliputiana has both blue flowers and nectar guides.

Veronica benthamii (Bentham's hebe), SW Cape, Auckland Island.