The intimate living together of plants and animals, where such an association is of mutual advantage, is called symbiosis. This is a general term that applies to many kinds of organisms but we shall confine ourselves to a single example, to the living together of plants and insects, more specifically ants.
This phenomenon is frequently encountered in the wild and plants ‘aid and abet’ the ants in various ways. Some species of Acacia, for example, have thick hollow spines that are partly open, forming a sort of ‘entrance’ for the ants that live in these spines. In some species of Tillandsia the hollow base of the sheaths is also inhabited by ants. To facilitate access the leaves are covered with thin ‘windows’ which the ants readily bite through, thus gaining entry themselves. What is the reason for this? The ants are protected against enemies without having to build a complex structure themselves and in return they provide the host plants with protection against pests on which they generally feed as well as with food remnants (which in the case of the given epiphytic bromeliad are a welcome fertilizer).
Some plants, such as the myrmecodia, have developed ‘artificial ant nests’ in their body tissues. Myrmecodia grows from a largeinterlaced with several ‘stories’ of tunnels inhabited by ants. Rising from the tuber is a short stem with large flat leaves. The entire plant is rarely more than 25 cm (10 in) high. Very similar is M. platytrea from Australia (the species is from Malaysia), which is equally common in botanical gardens. Other species, which number approximately 20, are very rarely grown.
The biologically very similar genus Hydnophytum is occasionally represented in botanical gardens by the species H. formicarum, which has smooth tubers with several stems.
Myrmecodia echinata (syn. M. tuberosa, M. iner-mis) has no special requirements and thrives even in warm centrally-heated homes. It is grown either simply on bark or in a light epiphyte mixture composed of sphagnum moss and fern roots plus some crushed bark and charcoal. It is readily propagated by sowing the seeds, as soon as the berries are ripe, into the same compost.