Hebe Pubescens Subsp. Pubescens On Rotoroa Island, Western Hauraki Gulf
Hebe pubescens (Benth.) Cockayne et Allan subsp. pubescens has long been regarded as endemic to the Coromandel Peninsula. There it is widespread occurring from Cape Colville south to the Kauaeranga Valley in the west and near Waihi in the east. However, during 1992 it was collected from a remote headland at the eastern end of Papanui Point, Tawhitikino Beach, near Clevedon. That record though accepted by Bayly et al. (2003) was later rejected in the recently published Hebe monograph (Bayly & Kellow 2006: p. 274) because a critical investigation of the specimens on which that record are based showed that they were hairy H. stricta (Benth) L.B.Moore var. stricta – a decision made chiefly because a duplicate of the gathering examined at AK after Bayly et al. (2003) was published lacked a sinus (M. J. Bayly pers. comm.).During a November field trip members of Auckland Botanical Society discovered a large population of Hebe pubescens subsp. pubescens on Rotoroa Island. Plants were noted growing in close association with another near Coromandel endemic, Pomaderris rugosa Cheeseman, and were abundant. Critical examination of the leaf bud sinus showed that as with other populations on the main Coromandel Peninsula while the sinus was usually seen, in some plants it was weakly developed, and in varying proportions on the same plant, and in others altogether absent.
The discovery of a large population of H. pubescens subsp. pubescens on Rotoroa Island adds support to the validity of the Papanui Point Record reported on by Bayly et al. (2003), and accords with our present understanding of the development of the Hauraki Depression and the Firth of Thames and also the impact that this recent geological feature has had on the biogeography of the flora and fauna of the inner Hauraki Gulf Islands.
Herbarium vouchers of the Rotoroa Island Hebe pubescens subsp. pubescens find have been lodged at the Auckland Museum herbarium.
References
Bayly, M.J; de Lange, P.J.; Mitchell, K.; Markham, K.R.; Garnock-Jones, P.J.; Kellow, A.V.; Brownsey, P.J. 2003: Geographic variation in morphology and flavonoid chemistry in Hebe pubescens and H. bollonsii (Scrophulariaceae), including a new infraspecific classification for H. pubescens. New Zealand Journal of Botany 41: 23-53.
Bayly, M.J.; Kellow, A.V. 2006: An illustrated guide to New Zealand Hebes. Wellington, Te Papa Press.
Posted: 13/11/2006