It is a widely distributed fern species in the southern hemisphere, with a natural range including New Zealand, Australia, and South America.

The laminae of both sterile and fertile fronds are pinnatisect, linear to narrowly elliptic, tapering to a pinnatifid apex, and coriaceous, with free veins.

[4] In the North Island, Blechnum penna-marina is found in the lowlands to alpine regions, extending from Hamilton and East Cape to south Wellington.

[4] The wide geographic distribution of Blechnum penna-marina highlights its adaptability to diverse habitats and climates across the southern hemisphere.

[7] These grasshoppers inhabit areas with vegetation covering the ground and can be found in alpine environments where Little Hard Fern grows well.

[7] While these grasshoppers are considered endemic to New Zealand, their presence indicates a potential interaction between the fern and native herbivores in other ecosystems.

[7] The impact of these grasshoppers on the population dynamics and growth of Blechnum penna-marina warrants further investigation, as it may play a role in shaping the fern's distribution and abundance in its natural habitat.