Sophora microphylla < Species index > Streblus heterophyllus
This article was first published in the Tararua Tramper Volume 94, # 0, September 2023
September in the hills with Michele Dickson, Chris Horne
Streblus banksii, Ewekuri, Large-leaved milk tree
Photo: Jeremy Rolfe
Origin of the botanical names
‘Streblus’ is derived from the Greek word ‘streblos’ meaning ‘twisted’, referring to the zig-zag pattern of the branchlets; ‘banksii’ refers to Sir Joseph Banks (1743-1820), British naturalist on Cook's first voyage to New Zealand in 1769-1770. The large-leaved milk tree, previously named Paratrophis opaca, is one of three New Zealand species of Streblus, members of the family Moraceae which also includes mulberry, fig, breadfruit and jackfruit trees. All plants of the family contain a milky latex.
Distribution and habitat
the large-leaved milk tree is endemic to Aotearoa / New Zealand. It grows in coastal and lowland forests and forest margins on Te Ika a Māui / North Island, from Kaitaia southwards, and on coastal sites on Te Waipounamu / South Island in Pelorus and Queen Charlotte Sounds, Tasman Bay and Golden Bay.
Growth habit
Ewekuri grows up to 12 m tall with a trunk up to 80 cm diameter. The smooth bark is pale grey to dark brown. The branchlets are slightly hairy when young and have numerous corky lenticels through which gases escape. The juvenile leaves, 2-6 x 1-3 cm, are elliptic-oblong in outline, are often deeply lobed, and have shallow rounded teeth. The adult leaves, 3.5-8.5 x 2-3.5 cm, are on petioles / leaf stalks up to 1 cm long. The egg-shaped leaves are alternate. They have many shallow, rounded teeth and are attached to the petioles at the broad end. Look on the underside to see the obvious vein network and the raised main vein and side veins. Ewekuri and tūrepo often hybridise, making it difficult to distinguish between them. Ewekuri generally differs from tūrepo by virtue of its non-divaricating growth habit, larger leaves and drupes.
Reproduction
The large-leaved milk tree has small male and female flowers on separate plants. The tiny pale yellow flowers have no petals and are arranged on drooping inflorescences, the male up to 25 mm long and densely flowered; the female widely spaced up to 15 mm long. They are pollinated by the wind. The fruit are red and up to 5 mm diameter. Flowering is in spring and fruiting from mid-summer to autumn. Factors which put the fate of ewekuri at risk:
the palatability of the seeds to rats
the scattered nature of the populations of ewekuri
the fact that female and male flowers appear on separate trees
infestations of witches' broom, caused by tiny mites which inject hormones or enzymes into the young inflorescences. These mites can also affect the small-leaved milk tree (see August Tramper).
Uses
The milky juice exuded from the bark when damaged was used by colonists in tea, in place of milk.
Where can you find ewekuri / the large-leaved milk tree?
Look for it in Ōtari-Wilton's Bush, Trelissick Park, East Harbour Regional Park, Whareroa Farm Park, Raumati Escarpment Reserve, in Waikanae's E. C. Russell Reserve and Ngā Manu Nature Reserve and in the Remutaka and Aorangi ranges.
In The Hills 2023-08 < Index chronological > In The Hills 2023-10