The New Zealand Plant Conservation Network

I would like to know what causes the spots on P. tenuifolium leaves. Where I live the near the coast it is quite windy and the leaves on P. tenuifoliun are very spotty. I have seen garden plants of this species which are not covered in spots. The new leaves are a beautiful delicate light green. I also note that Mapou always has similar looking spots, which are already present in new leaves as is a red margin, the spots are called pellucid glands I believe, in Mapou. Is this the same thing in P. tenuifolium? Does anyone know about them? Sorry no photos as I have no way to load photos of small enough size to go in the forum.

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Hi Kath, there are usually two types of blotching common in M. australis leaves, the small dark dots which are the pellucid glands present in all NZ Myrsine (but they vary in how obvious between different species) and a larger usually back indistinct-edged blotching that is caused by a fungus growing on the leaf surface (in Myrsine divaricata there is a third dark blotch at the base of the leaf which is a dark pigment within the leaf). This fungus grows (naturally) so older leaves have more of their surface covered. Pittosporum tenuifolium (and many other NZ plants) also has dark blotching caused by a fungus, but I do not know if it is the same species as occurs in M. australis. You could email David Orlovich at the University of Otago (david.orlovich@otago.ac.nzwho is a specialist in fungi. There is also another reddish blotching that P. tenuifolium leaves are particularly prone to. This is a natural pigment (anthocyanin from memory) which acts as a protector to the leaf (sunscreen)

Continued. This pigment is common in many NZ plants (NZ's high UV exposure?) and is often seen as a red margin on the leaves of alpine plants particularly