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Plant Focus

Quercus macdougallii
A rare oak endemic to the Sierra Juárez in Oaxaca

Rare Mexican Oak Pops Up in Palmerston North

Last April, Australian IOS member Peter Marshall and I visited Massey University at Palmerston North, New Zealand, kindly hosted by Grounds Manager Gary Mack and Grounds Supervisor Dave Bentley. The beautiful park where the University stands is home to a fine collection of plants, said to number 11,000 different species, including around 35 oak taxa. We saw many interesting trees, but one turned out to be a rare surprise.

Q. heterophylla
One of the larger oaks at the Manawatu Campus of Massey University, possibly Quercus ×heterophylla

Gary and Dave were especially keen to show us an oak that was as yet unidentified. It had been found as a "weed" growing in a pot obtained from a local nursery (the former Top Trees Nursery in the Hawkes Bay Region), next to the plant that had been acquired. It caught the eye of the previous Grounds Manager Dave Bull—training at Kew might have helped sharpened his eye for the out of the ordinary—and rather than pluck and discard it, he transplanted it to its own pot and eventually it was planted next to one of the iconic buildings on campus. It is now a large young tree, and there have been suggestions that it should be removed so as not to hinder the passage of vehicles around the building.

Q. sartorii
Leaf from the putative Quercus sartorii at Massey University

When we saw the tree, my first thought was that it might be Quercus acutissima, based on the fine teeth on the leaf margins. But closer inspection indicated it was something else: the bark suggest a Red Oak (section Lobatae), as did the aborted acorns that littered the ground. Eventually I realized that it was most likely Q. sartorii, a relatively rare Mexican oak (for some authors a synonym of Q. xalapensis).

aborted acorns
Aborted acorns

One of the first steps when identifying an oak is to consider what it is likely to be, based on the location, the possible parents knowing to be growing in the vicinity, etc. When examining a volunteer seedling in a university campus in New Zealand’s North Island, a rare Mexican oak would normally not have been part of that consideration. So how could such an oak have popped up in a nursery pot?

Q. sartorii 2
Putative Quercus sartorii at Massey University (left to right): leaves on branch, bark, and terminal buds

The answer probably has all to do with legendary New Zealand oak collector Bob Berry, who collected acorns in Mexico in the 80s and 90s and established a world-class collection in Hackfalls Arboretum, near Gisborne, about 400 km northeast of North Palmerston. We must surmise that the nursery had collected seed at Hackfalls, and an acorn from one of the several Q. sartorii at Hackfalls inadvertently dropped into the pot where the other oak was grown. It is a fine tree, over 15 meters tall and well structured. Let’s hope Gary and Dave can persuade authorities at Massey to let it remain where it stands. The University currently has a project to create a botanic garden that will available for research and teaching, both to the community across New Zealand and internationally. The garden will generate a wealth of information on restoration methods and the management of rare, threatened, and endangered plants from around the world. This would be the first research-led botanic garden in New Zealand. An established specimen of Q. sartorii would be a jewel in the crown of such an institution.

Q. sartorii 3
Quercus sartorii (?), flanked by Gary Mack (left) and Dave Bentley (right). Peter Marshall, in classic quercophile pose, scours the ground for acorns.
Q. sartorii Hackfalls leaves
A twig from one of the Quercus sartorii at Hackfalls Arboretum (#1987 065), a possible source for the tree at Massey University © Bob Berry
Q. sartorii Hackfalls tree
Quercus sartorii at Hackfalls Arboretum (#1987 065), perhaps mother to the volunteer at Massey


Photos © Roderick Cameron, unless otherwise specified