[2] Fertile pinnules in P. macilenta are similar in shape to sterile ones, and sori are usually copious and short, along sinuses, with the tips of segments barren.

[5] It predominantly occupies coastal and lowland areas, extending into montane districts, albeit rarely in the central North Island.

[5] In the South Island, the species is commonly found in coastal and lowland regions between the Marlborough Sounds and Greymouth, and up to 520 meters near Nelson.

[5] P. macilenta prefers habitats ranging from coastal to montane regions in northern areas, predominantly occupying dry, less vegetated sites within forests.

[4] Its growth is commonly in a variety of settings including more open kauri, podocarp, beech, and broadleaved forests, as well as under manuka and kanuka scrub and Carex secta.

[6] Pteris species typically showcase rapid germination, leading to the early development of the gametophyte, which can vary in form based on the environmental conditions and the presence of factors like antheridogens.

Gametophytes are typically cross-fertilized, and under moist conditions without direct watering, they can become long-lived, changing shape and continuing to produce sex organs.

[2] Pteris macilenta favors soils in coastal to montane habitats, predominantly on alkaline rocks like limestone, indicating specific nutrient preferences.

[5] Found in shaded or semi-shaded environments, its distribution ranges from preferring clay slopes under karaka trees to adapting distinctively in limestone areas.

[11] All samples showed mycorrhizal infection, indicating a strong symbiotic relationship that aids in nutrient uptake and overall health.

Additionally, small quantities of ectotrophic mycorrhizas similar to those found in certain tree species were present, suggesting a diverse fungal community within the fern’s root system.

[13] Morphologically, P. macilenta is likely an allotetraploid, meaning it has double the usual number of chromosomes and likely evolved from two different species, though it lacks experimental evidence.

[5] All three species, P. macilenta, P. saxatilis, and P.carsei, share nearly identical rbcL gene sequences, indicating a close genetic relationship.

The lectotype designation by Brownsey and Perrie in 2020, based on original material collected during the voyage of the Astrolabe, aimed to clarify the identify of P. macilenta.

Despite these efforts, the historical application of the name and the existence of closely related taxa make the precise definition of P. macilenta challenging [5]