MANILA, Philippines – Asplenium nidus or Pakong Lalake is the most common Bird’s-nest Fern in the world. It may be found as far west as India, south in Brisbane, Australia and north to Japan. There are many forms, shapes and sizes that exist but the common denominator is the elevated rounded to angular/squarish midrib on the axial surface and flat abaxial side (some exhibiting a very small centrally positioned keel).
In Philippines, Asplenium nidus is called Pakong Lalake in contrast to Asplenium musifolium which is called Pakong Babae. This is basically based on the proportion of the leaves and shape of the leaftip. Pakong Babae (A. musifolium) is wider and has rounded tip whereas the Asplenium nidus has pointed leaftip and lamina are generally narrower.
The shape of the leaf actually does not help the taxonomy of the group of fern because there are other Bird’snest Asplenium species that have similar pointed leaftips (e.g. Asplenium anthrophioides, Asplenium collubrinum, Asplenium cymbifolium and Asplenium australasicum). To complicate it, there are some bio-types of Asplenium nidus that have rounded or fasciated leaftips.
Generally, Asplenium nidus can not reach the full size of Asplenium musifolium, although there are again exceptions: the Sumatran population of Asplenium musifoliums is smaller than Asplenium nidus. The easiest way to determine the species is to see if the midrib is on top or below.
For definitive identification, the leaf cross section should show the square midrib on top and more or less flattened lower area plus the mushroom-like vascular bundle. Other Asplenium species will give different degrees of X’s when the 2 base vascular bundle fuses. Only Asplenium nidus gives a mushroom-shaped vascular bundle.
Asplenium nidus have leaves coming out of the crown horizontally in contrast to Asplenium musifolium and australasicum that has fronds starting off vertical then moves horizontally as they mature. This is the simple guide is used by Australians to distinguish A. nidus from A. australasicum.
Asplenium nidus is one of the more important economic ferns. It is widely used as landscape material in the tropics and as food in Ryukus and Taiwan. The mutant forms have been collected by gardeners over the years. Collectors pay good prices for crestate, filiforms, fasciated, plicate and bifurcate forms.