Chromosome numbers of Australian and New Guinean species of Veronica (Plantaginaceae)

Abstract

New records of chromosome numbers are presented for eleven Australian species of Veronica sens. lat. Reference is also given to records previously published for ten species that have been referred to Derwentia, Parahebe or Chionohebe, but that are now included in a widely circumscribed Veronica. The species formerly included in Derwentia, Parahebe or Chionohebe exhibit secondary base numbers of x = 21, 20 or 19, whereas those formerly retained in Veronica have x = 18 (or 17). For the species formerly referred to Detzneria, from New Guinea, we present only a very approximate count of 2n = 38-42 which, however, differs from the previous report of 2n = 48.

New Australian species and typifications in Veronica sens. lat. (Plantaginaceae).

“…sect. Detzneria' but our studies (Briggs & Ehrendorfer 2006), although giving only a very approximate count, show 2n = 38-42. There may have been hexaploidy from a primary base number of x = 8 (as in V. sect.…”

“…Chromosome numbers are all polyploid, mostly on the secondary and reduced hexaploid base number x = 18, (2n = 36 or 72), only V. plebeia appears further reduced to 2n = 34, i.e. x = 17 (Briggs & Ehrendorfer 2006). No comprehensive survey of the clade is yet available, but treatments in the floras of South Australia (Barker 1986), New South Wales ) and Victoria (Briggs & Barker 1999) supply partial information, including brief descriptions and keys for the identification of the new taxa described here.…”

“…Veronica grosseserrata is octoploid (2n = 72) (Briggs & Ehrendorfer 2006). It can be distinguished from V. notabilis F.Muell.…”

“…Veronica sobolifera has a chromosome number of 2n = 72 (Briggs & Ehrendorfer 2006) and can be distinguished from Veronica gracilis R.Br., also octoploid, especially by its taller stems, larger and broader leaves with more serrations, racemes with more numerous flowers, and larger and broader calyx lobes. In V. gracilis stems are mostly 4-25 cm long, leaves 1-4.5 mm broad, entire or with 1-2 teeth on each side, racemes have 2-8 flowers, and calyx lobes are up to 2.5 mm broad.…”

“…Chamaedrys, x = 8). They are polyploids with 2n = 36 (rarely 2n = 34) and 2n = 72 and thus exhibit a secondary base number of x = 18 (rarely 17) in contrast to all other members of the 'Hebe complex' of Veronica (Heads 1992, Bayly & Kellow 2006, and other authors) which have secondary base numbers of x = 21, 20 and 19 (Briggs & Ehrendorfer 2006).…”