Mount Api is a limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

 located in Gunung Mulu National Park

Gunung Mulu National Park

Gunung Mulu National Park near Miri, Sarawak, Malaysian Borneo, is a UNESCO World Heritage Site that encompasses incredible caves and karst formations in a mountainous equatorial rainforest setting...

 in Sarawak

Sarawak

Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...

, Malaysia. Neighbouring Mount Benarat and Mount Buda are part of the same formation. Mount Api is famous for its striking limestone karst formations

Karst topography

Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...

, commonly called "the pinnacles".

Api Chamber

Api Chamber

Api Chamber is a chamber in Whiterock Cave in Mount Api, Gunung Mulu National Park, Sarawak, Malaysia. Measuring 300 m by 200 m and with a surveyed circumference of 900 m it is the ninth largest cave chamber by area in the world. Its height is over 100 m and its plan area is...

, the second largest chamber in Malaysia, was discovered on Mount Api during the Benarat 2005 Caving Expedition

Benarat 2005 Expedition

The Benarat 2005 Expedition to Gunung Mulu National Park, Sarawak in Malaysia took place between September 8th and October 7th 2005. The expedition was the latest in a series of Anglo-Sarawak cooperative activities which commenced in 1977...

.

Mount Api is notable for its pitcher plant

Pitcher plant

Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. It has been widely assumed that the various sorts of pitfall trap evolved from rolled leaves, with selection pressure favouring more deeply cupped leaves over...

 diversity, which includes at least eight species: Nepenthes campanulata

Nepenthes campanulata

Nepenthes campanulata , the Bell-Shaped Pitcher-Plant, is a tropical pitcher plant endemic to Borneo.Forest fires destroyed the only known population of N. campanulata in 1983 and it was uncertain whether the species had survived elsewhere or was in fact extinct. It was rediscovered in 1997,...

, Nepenthes faizaliana

Nepenthes faizaliana

Nepenthes faizaliana is a tropical pitcher plant endemic to the limestone cliffs of Gunung Mulu National Park in Sarawak, Borneo. It is thought to be most closely related to N. boschiana.-Botanical history:...

, Nepenthes hurrelliana

Nepenthes hurrelliana

Nepenthes hurrelliana is a tropical pitcher plant endemic to Borneo, where it has been recorded from northern Sarawak, southwestern Sabah, and Brunei. It is of putative hybrid origin; its two original parent species are thought to be N. fusca and N. veitchii...

, Nepenthes lowii

Nepenthes lowii

Nepenthes lowii , or Low's Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. It is named after Hugh Low, who discovered it on Mount Kinabalu...

, Nepenthes muluensis

Nepenthes muluensis

Nepenthes muluensis , or the Mulu Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. It grows in highland habitats at elevations of 1700 to 2400 m above sea level.-Botanical history:...

, Nepenthes tentaculata

Nepenthes tentaculata

Nepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi...

, Nepenthes veitchii

Nepenthes veitchii

Nepenthes veitchii |James Veitch]], nurseryman of the Veitch Nurseries), or Veitch's Pitcher-Plant, is a Nepenthes species from the island of Borneo. The plant is widespread in north-western Borneo and can also be found in parts of Kalimantan. N...

, and Nepenthes vogelii

Nepenthes vogelii

Nepenthes vogelii is a tropical pitcher plant endemic to Borneo. It is thought to be most closely related to N. fusca.-Botanical history:...

.