Thursday, 31 May 2018

Unusual Trees of Aotearoa - cauliflory and ramiflory

My recent blogpost about kohekohe trees got a lot of interest, with people particularly curious about cauliflory.
Flowering kohekohe trees
caulifory describes trees that flower from the trunk and major branches rather than the more common flowering from the tips of branches among the leaves


Kohekohe flowers sprouting from the trunk
On a recent nature ramble through kohekohe in Porirua Scenic Reserve, I was asked what other trees were examples of cauliflory. On the spot I could only think of mahoe, but was corrected by a friend who pointed out the mahoe is an example of another unusual form of flowering called ramiflory. Who would have thought we'd have such unusual trees!
ramiflory describes trees that flower (and therefore fruit) from its branches, but not the trunk
Mahoe berries sprouting from the branches.
Its flowers are white and less conspicuous than the berries.

Looking up Dawson and Lucas's New Zealand's Native Trees, I see that another tree that exhibits cauliflory is kōtukutuku (tree fuchsia). Unfortunately, we don't often see it flowering as like kohekohe it is a favourite food of possums the best place to see it flower in Wellington is probably Zealandia.

Anther tree whose flowers are an example of ramiflory is toro. We often notice young toro as we climb up in the forest, perhaps around 400m upwards, so I tend to think of it as a higher altitude tree, however it grows in lowland forests too. It flowers from late winter to mid-summer.

A young toro 
Why trees flower like this is subject to much speculation. Flowering below the canopy may attract pollinators such as insects, lizards and bats (if only they weren't so rare). In New Zealand, birds such as tūī and korimako love the kohekohe.

The kohekohe forest is also strongly scented, although individual flowers don't seem to have a strong smell, but yesterday in Porirua Scenic Reserve there were so many flowers under the canopy the scent was rich and heady. Trying to describe the scent to those with a less keen nose was tricky, we resorted to the kind of words used for describing wine - tropical, citrusy and so on. In the end we agreed that kohekohe scent was a close match to Gewuerztraminer!