This article was published in The Fringe, March 2015 ...
Kahakaha - 'Widow maker'
An observer with some knowledge of native plants could be forgiven for thinking this is a member of the Astelia genus. Indeed a couple of Astelias can often be found growing alongside this lily, perching as an epiphyte high in the branches of some sturdy tree.
The Collospermum is generally a thicker, heavier looking clump than the Astelias, but the best identification is to peer into the base of the clump and the Collospermum leaves change from the light, bright green to a dark brown almost black fan radiating out in a semi-circle. Below this cluster of fans hangs a skirt of old dried leaves which frequently obscures a clear view of the plant above. As the plants mature they increase in size and weight holding litres of water as reservoirs in their folded leaves. By this method the need for deep soil and moisture is dispensed with and the plants retain their own water supply, which they share with visiting birds wanting to quench their thirst - and if the plant is in luck the bird deposits some rich nutrients within the leaves to sustain the plant.
Kahakaha is a long-lived plant and if the supporting tree is strong enough a large colony develops, each fan anchored into the roots of those older than it. In time the new colonists are forced to grow, not above the supporting branch, but suspended in space, held only by their interlocked root systems. On occasions this construct proves inadequate to hold the increasing weight, and substantial clumps fall to the ground. Anyone unfortunate enough to be passing underneath the clump at that moment understands the derivation of the common name 'widow-maker' that old bushmen bestowed upon the Collospermum.
Found throughout the North Island and the top of the South Island, Collospermum is tolerant of a range of conditions but prefers dry shade to grow best. The stiff upright foliage grows to well over a metre long and 8cm wide while the flowers grow on a cluster of pendulous racemes or stalks about 50cm long. The plants are dioecious meaning the male flowers are on one plant and the females on another. The flower clusters are a handsome mix of cream and green flowers with a silvery bract at the base, and the female flowers mature into orange/red fruit which ripen to a translucent lustre.
Of course, to produce the fruit it is necessary to have both sexes within a reasonable proximity, e.g. within the same hectare, so pollinating insects can locate and fertilise the female after visiting the male and collecting its pollen.
There are only four Collospermum species with two in New Zealand, one in Samoa and one in Fiji. Collospermum microspermum is the other local species. It is less common and slightly smaller with narrower leaves and long white panicles of flowers .