The Aquatic Aroid Cryptocoryne and Its Habitats in Malaysian Borneo
Author: Lo Shiang Huei (Michael Lo)
The author, a native of Malaysian Borneo, details his experiences collecting the many species of Cryptocoryne growing wild in the waterways of his homeland.
My New Discovery
It was the year 2004 when I first discovered a beautiful aquatic plant growing on the submerged tree roots in a river at the Bau area of western Sarawak. At that time I did not know what it was, as I had never seen such a water plant before in my lifetime. After searching for information through the Internet, I found out that it was a species of aquatic aroid in the genus Cryptocoryne. In my country of Malaysia it is also known as “Keladi Air.”
There are more than 20 species of Cryptocoryne in Malaysia. Most of them are found in the Sarawak state of East Malaysia, located in the northwestern side of the third largest island in the world, Borneo.
The Internet helped me a lot in communicating with scientists and hobbyists from overseas to exchange information and knowledge about how to cultivate and identify each species of Cryptocoryne that I found in the rivers of my homeland. The following are the many kinds of Cryptocoryne found in the swamps and rivers of Sarawak : C. auriculata, C. bullosa, C. ciliata, C. cordata var. grabowskii, C. cordata var. zonata, C. ferruginea, C. keei, C. lingua, C. longicauda, C. pallidinervia, C. striolata, C. uenoi, C. yujii, C.zaidiana, C. x purpurea, and C. sp. “Batang Ai.”
Different species of Cryptocoryne plants grow in different types of habitats. Most of them grow in submerged conditions, in the shady regions of streams, rivers, and swamps. Some grow in emersed conditions, near the water’s edge but under the shade of the forest where the humidity is very high.
Cryptocoryne in Swamps and Blackwater Rivers
There are seven species of Cryptocoryne found in the freshwater and peat swamps in Sarawak. Most of them have very large rounded leaves and they can grow to be extremely big in size.
Cryptocoryne cordata var. grabowskii
In 2004, when I was searching for a beautiful fish called Sundadanio axelrodi in a small blackwater river in the peat swamp forest near Kuching City, I found this species of Cryptocoryne. This species is a variety of the cordata species, and it grows on the peat soil in submerged conditions. Only a few are found growing in emersed conditions on the fallen tree logs near the water’s edge. All of them grow near the blackwater rivers where the water’s pH is very low. So far, black water is the only known locality for this crypt. It is facing the threat of extinction because its habitat is next to areas of rapidly expanding housing.
Cryptocoryne cordata var. zonata
This aroid is another variant of the C. cordata complex. The spathe has a very bright yellowish color. It is found in the swamps and blackwater streams or rivers near the coastal area of Sarawak. Most of them grow in submerged conditions, under the shade of the forest. There is a patch of this species growing under direct sunlight in a blackwater river at Seri Aman. However, most of the Cryptocoryne in that river died during the land clearing activity at the riverbank early in 2006. That sudden change in the environment was the main factor leading to the death of almost all the Cryptocoryne in its natural habitat.
The distribution of this species is very wide in southwestern parts of Sarawak. It is mostly found in freshwater swamps where the water is very soft. I also found it growing in a stagnant pool at the base of a limestone hill at Bau where the pH is around 7.2. In the past it was reported to be found in a suburban area of Kuching City, but due to development, most of the plants there are already destroyed. This species is very easy to cultivate in the aquarium.
Cryptocoryne longicauda is one of the common species of aquatic aroids from the peat swamp forests of Sarawak. The coverage area is very wide. It is mostly found in the black and acidic waters of streams near the coastal area. It has a long and dark red colored spathe. The spathe and its tail can reach 20 cm (8 inches), hence its name longicauda, which means “with long tail” in Latin. In some places it grows together with Cryptocoryne cordata var. zonata.
The coverage area of this species is in the lower part of the Sungai Rajang, the longest river in Malaysia. It only grows in the black water of peat swamp areas. The spathe is yellowish and reddish colored with very fine red spots. It is not easy to cultivate it in the aquarium, as it prefers to grow in soft water. I only cultivate this species in emersed conditions in a terrarium. The best substrate for planting this aroid is peat or compost soils.
This species was first discovered by the Japanese plant collector Yuji Sasaki in 2002. It grows in the blackwater streams and rivers on the eastern side of the area of Sibu. The leaf is light-green colored, and can reach at least 40 cm (16 inches) in length. The spathe is white in color and has a distinct dark-purple collar.
Cryptocoryne x purpurea
C. x purpurea is the rarest species of aquatic aroid in my homeland. It was discovered not long ago in the middle part of the Batang Kayan Basin in western Sarawak. It is a natural hybrid species that grows in a ditch in a shaded old rubber plantation. The spathe is red colored.
Cryptocoryne in Jungle Streams and Clearwater Rivers
There are five species of Cryptocoryne found in fast-flowing rivers or streams where the water is less acidic (the pH is usually between 6 and 6.8). Most of them are growing on the submerged tree roots or gravel in the riverbed to avoid being washed away by strong water currents, especially after a heavy rainfall.
This aquatic plant is mostly found growing on the tree roots either in submerged or emersed condition. They usually grow together in very small patches, under the shade of big trees near the riverbank. The spathe is very short and it is white colored. The distribution area of this plant includes the lower part of the Sungai Rajang. The Rajang River Basin is the center of the biodiversity of this aquatic aroid in Malaysia.
Cryptocoryne bullosa is very common in clearwater rivers and streams in the central part of Sarawak. The coverage area is from Batang Balingian near Bintulu to the northern part of Sungai Saratok. A very big population of this species was found in a tributary of Sungai Rajang. However, this species is also facing the threat of extinction due to the deforestation in the Sungai Rajang Basin. It is reported that this plant is not easy to grow in cultivation. Some of the plants I collected have an almost black-colored leaf. The spathe is very short, about 4 cm (1½ inches) long with a red-colored limb.
This species was found by local collector Henry Ong Kee Chuan in 1978, and it is named after him. This plant grows in the clearwater rivers near Bau. Bau is a limestone hill area where the water in the river is a bit hard (pH between 7.0 and 7.4). In some areas it only grows on the submerged tree roots, where it avoids being washed away by the water current. In 2006, I found this species in a slightly acidic tea-colored river in the northern part of Bau. I was surprised by what I discovered, as in the past it was thought to be a plant that only grows in hard-water areas.
This species is the second most common species in Sarawak, after C. ciliata. In its various localities it has different variation in the leaves. Some of the old leaves are almost black colored, but the young leaves are mostly bright green or brownish in color. There is a patch of this species in Betong that only grows on the submerged rock surface of the river bed. Mostly, it grows on the submerged tree roots in the river where the water current is strong. It has a very slender spathe.
Cryptocoryne sp. “Batang Ai”
During my recent expedition to Batang Ai in the eastern part of Seri Aman, I found an unidentified species of Cryptocoryne growing together with Cryptocoryne striolata in a clearwater river. Due to the population of this species being too small, I was unable to send some specimens to scientists overseas to find out what it was. Nevertheless, I will return to that place and search for it in the near future. I hope I can find the spathe, which is the key to identifying this beautiful water plant.
Cryptocoryne in Brackish Water and Freshwater Tidal Zones
This is the most common species in Sarawak. It is mostly found in either open space or under the shade of the mangrove forest in brackish-water tidal zones where it is very close to the coast. It is the biggest and tallest Cryptocoryne from Sarawak, growing up to one meter (about 3 feet)! It is also found growing at the mud bank with C. lingua in freshwater tidal zones in the middle part of Sungai Sarawak.
This aquatic plant grows on the mud bank, under the shade in the freshwater tidal zone. Its leaves are very thick and spoon shaped. The limb of the spathe is yellowish colored with fine red dots. The coverage area of this species is very wide. It can be found in the rivers of southern Sarawak to the lower part of the Rajang River in the central part of Sarawak. In the Rajang River Basin it usually grows in very open areas where the leaves are covered by a thick layer of mud. This mud prevents the leaf from being burned by the scorching tropical sunlight.
This is a new species discovered by Dr. Isa Ipor, a researcher from a local university in Sarawak. It is named after one of the governors of Sarawak, the late Tun Ahmad Zaidi Adruce, and is only found growing on muddy ground at the riverbank where the river is a tributary of the Sungai Tinjar in the Miri area of northern Sarawak. The leaf looks a bit like Cryptocoryne lingua. The spathe is about 14 cm (5½ inches) long, and whitish colored with very fine purple spots.
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