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Forest Vines to Snow Tussocks: The Story of New Zealand Plants

Bud Protection

Bud Protection

Unlike many trees of temperate climates, where the immature leaves at the branch tips are protected during the winter by dry overlapping scales, the buds of many tropical trees of moist climates are not pro-
Figure 24 Tarata or lemonwood (Pittosporum eugenioides). Overwintering buds with overlapping bud scales.Photo: M. D. King.

Figure 24 Tarata or lemonwood (Pittosporum eugenioides). Overwintering buds with overlapping bud scales.
Photo: M. D. King.

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in this way. This is understandable as they are not subject to an unfavourable season. Nevertheless the delicate immature leaves are at some risk of drying out and they may be protected by a layer of hairs or by mucilaginous or resinous secretions. The petiole bases of mature leaves adjacent to a bud may also afford some protection by partly enclosing it with or without the assistance of paired appendages known as stipules.

In this respect the woody flowering plants of the New Zealand conifer broadleaf forest seem comparable to those of the tropics. Of 45 genera only 3 have numerous, relatively large bud scales — Pittosporum (Fig. 24), Aristotelia and the tree species of Metrosideros. In the beech forest (see Chapter 5) the species of Nothofagus also have many overlapping bud scales.

Nineteen genera have no bud protective structures at all although the immature leaves are often hairy (Fig. 25). Admittedly, genera in this group with strong tropical affinities, for example Dysoxylum, Vitex, Beilschmiedia, Litsea, are represented by only one or two species in New Zealand.

The remaining genera afford their immature leaves partial or complete protection with a few small scales or with the stipules or sheathing bases of adjacent mature or developing leaves. Some also form protective secretions such as mucilage in Coprosma and a varnish-like material in some species of Pseudopanax.

Figure 25 Rewarewa (Knightia excelsa). Very young leaves with a furry pubescence, but otherwise unprotected.Photo: M. D. King.

Figure 25 Rewarewa (Knightia excelsa). Very young leaves with a furry pubescence, but otherwise unprotected.
Photo: M. D. King.