Cyathea javanica 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 Java

Java

Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...

 and Sumatra

Sumatra

Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

, where it grows in rain forest and on riverbanks at an altitude of 250-1500 m. The trunk of this plant is erect and up to about 10 m tall. 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 may be bi- or tripinnate and 2-3 m in length. 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 spiny and bears scattered scales

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...

 throughout. These scales are dark and have fragile edges. C. javanica has round 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....

 which are borne near the midvein of fertile pinnules . They are protected by firm, flat indusia that are saucer-like in appearance.

C. javanica appears to be most closely related to Cyathea doctersii

Cyathea doctersii

Cyathea doctersii is a species of tree fern endemic to Sumatra, where it grows in forest at an altitude of approximately 150 m. The trunk is erect and 2-3 m tall. Fronds are bi- or tripinnate and 2-3 m long. The stipe is covered with scattered flat, brown scales and some hairs...

. Large and Braggins (2004) note that C. doctersii may in fact be of hybrid origin between C. javanica and a member of the Cyathea latebrosa

Cyathea latebrosa

Cyathea latebrosa is a common and widespread species of tree fern native to Indochina. Its natural range covers Cambodia and Thailand, and stretches from the Malay Peninsula to Indonesia, where it is present on the islands of Borneo and Sumatra. Plants reported from India and Sri Lanka have thinner...

complex.

When Carl Blume described C. javanica he also named one variety, C. j. var. rigida. Braggins and Large (2004) note that "although variety rigida is apparently part of the C. javanica complex, the name has also occasionally been associated with Cyathea polycarpa".