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

Species and Varieties of New Zealand Beech

Species and Varieties of New Zealand Beech

Five species of Nothojagus were formerly recognised in New Zealand, but more recently two of these have been combined as varieties of one species.90

Nothofagus menziesii: silver beech (the bark is white and silvery particularly in young trees).

Nothofagus fusca: red beech (the timber is reddish in colour).

Nothofagus truncata: hard beech (the wood has a high silica content making it hard).

Nothofagus solandri var. solandri: black beech (the bark is very dark partly due to the growth of a sooty mould).

Nothofagus solandri var. cliffortioides: mountain beech (grows mainly at higher altitudes than the other beeches).

Silver beech has thick, almost circular leaves, 0.5-1.5 cm long and wide, bearing a few domatia on the underside and small, rounded marginal teeth often in pairs (Fig. 69). The leaves of red and hard beech are similar to each other, 2-4 cm long by 1.5-2.5 cm wide and with saw-like marginal teeth. Hard beech has rather thicker leaves with 8-12 page 122teeth per side compared with 6-8 for red beech; red beech alone has domatia. Black and mountain beech have small smooth-margined leaves, hairy below, 1-1.5 cm long by 0.5-1 cm wide. It is difficult to distinguish the leaves of the last two forms. Mountain beech at higher altitudes often has leaves that taper from the base, while the leaves of black beech at low altitudes are oblong, but there are intergrading forms in many places.

Silver, hard and red beech may become large trees 30 m or more in height with trunks 2 m or more in diameter. The trunk bases of the
Figure 69 Silver beech foliage and young fruits with glandular hairs. Photo: M. D. King.

Figure 69 Silver beech foliage and young fruits with glandular hairs. Photo: M. D. King.

page 123first two have low, rounded buttresses while those of the latter are high and narrow. The larger trees of mountain and black beech are generally below 25 m in height with unbuttressed trunks of about 1m in diameter.

The bark of all the beeches, except when young, is rough and fissured. The tree crowns, especially in more open situations, are wide and deep and particularly in mountain and black beech, the foliage is often arranged in distinctive horizontal layers. The male and female flowers at the tips of twigs are wind-pollinated and inconspicuous, although in good flowering years coloured anthers in the male flowers may impart a reddish glow to the crowns of black and mountain beech particularly. More brilliant splashes of colour, contrasting with the dark green of the foliage, may be provided by certain mistletoes which commonly parasitise the beeches. Peraxilla colensoi, usually found on silver beech, and 2 tetrapetala have bright red flowers. Alepis flavida with orange-yellow to yellow flowers used to be common, but has now been depleted by opossums. Heavy flowering of all the beech species in New Zealand takes place every few years with little or no flowering in the other years. It is suggested that 'flowering years' follow hot summers which encourage the initiation of flower buds.91 buds.91

The beech seed are 5-8 mm long with narrow wings. It is considered that they are not capable of being dispersed for more than a few kilometres and then only with strong winds.92

Silver beech stands apart from the other species in several respects. Some of the more striking differences are:

(a)each leaf of a silver beech generally lasts several years before falling, those of the other species last for only one year, generally falling a few weeks after the new season's leaves have unfolded, or even, in the cases of occasional trees of red and hard beech, a few weeks before;
(b)natural hybrids have often been observed involving all species except silver beech;
(c)silver beech is the only species attacked by a fungus, Cyttaiia, whose orangey, golf-ball-like fruiting bodies may be abundant on the branches of some trees;
(d)study of the pollen of the New Zealand beeches has shown that silver beech has a different form of grain from that shared by the other species.
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For the last reason our species have been assigned to two informal groups within the genus, both of which are also represented in Australia and South America — the 'menziesii group' and the 'fusca group'. A third 'brassii group', with a third pollen type, is restricted at present to New Caledonia (Fig. 70) and New Guinea.93

Figure 70 New Zealand and New Caledonian Nothofagus leaves.New Caledonia: Nothofagus codanandra; A, juvenile leaf; B, adult leaf; C, twig with a cupule with 3 flat seeds; D, Nothofagus sp.; E, Nothofagus equilateralis.New Zealand: F, Nothofagus fusca (red beech); G, N. truncata (hard beech); H, N solandri var. clijfortioides (mountain beech); I, N. menziesii (silver beech); J, N. s. var. solandri (black beech).Photo: M. D. King.

Figure 70 New Zealand and New Caledonian Nothofagus leaves.
New Caledonia: Nothofagus codanandra; A, juvenile leaf; B, adult leaf; C, twig with a cupule with 3 flat seeds; D, Nothofagus sp.; E, Nothofagus equilateralis.
New Zealand: F, Nothofagus fusca (red beech); G, N. truncata (hard beech); H, N solandri var. clijfortioides (mountain beech); I, N. menziesii (silver beech); J, N. s. var. solandri (black beech).
Photo: M. D. King.

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Figure 71 Nothofagus forest in the Travers Valley, northern South Island. Note the even treeline. Photo: J. W. Dawson.

Figure 71 Nothofagus forest in the Travers Valley, northern South Island. Note the even treeline. Photo: J. W. Dawson.