Cyathea costalisora is a species of tree fern

Cyatheales

The order Cyatheales is a taxonomic division of the fern subclass, Cyatheatae, which includes the tree ferns. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicates that the order is monophyletic. Some species in the Cyatheales have tree-like growth...

 native to western New Guinea

New Guinea

New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

, where it grows on the edges of forest and in moist hollows at an altitude of 1900-3225 m. The trunk is erect, up to 4 m tall and may branch near the base. Frond

Frond

The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...

s are bi- or tripinnate and 1-1.5 m long. The stipe

Stipe (botany)

In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....

 is warty, especially where scale

Scale (zoology)

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

s have fallen. The scales are pale and have a distinctive dark glossy central region, with a paler dull margin. Sori

Sorus

A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....

 are round and occur near the fertile pinnule midvein. They are covered by firm, dark indusia that are cup-like in appearance.

C. costalisora should not be confused with the similarly named Cyathea costulisora

Cyathea costulisora

Cyathea costulisora is a species of tree fern native to Sumatra. The trunk is erect and usually 1-4 m tall. Fronds are bi- or tripinnate and 1-2 m long. The stipe is covered with warts and scales. The scales are either pale and glossy or dark and flat. Sori occur near the fertile pinnule midvein...

.