Aponogeton

Lore & Background

The name Aponogeton was published in 1782 and is derived from a geographic location neighboring the Apono tribal district of coastal Gabon. The genus is distributed in tropical to warm temperate regions of Africa, Asia, and Australasia. Individual plants are not always easy to identify due to hybridization, particularly those sold as A. crispus, which are often cultivated hybrids with A. natans or A. rigidifolius. Generally, an Aponogeton from Asia will have a single bloom stalk, while those from African heritage (including Madagascar) will have multiple blooming stems on the same flower stalk.

The oldest known fossils of the genus are pollen from the Late Cretaceous of Wyoming, approximately 82-84 million years old, indicating that the genus likely originated in the Northern Hemisphere. Other fossil pollen is known from Canada and Greenland dating to the Eocene. Many species grow in temporarily still or flowing waters and live through the dry period as a dormant tuber. Most species grow from tubers, and the starchy tubercles of African species are able to survive the dry season by shedding their leaves and undergoing a dormant period.

Several species are used as ornamental plants in aquariums or ponds. The 1889 book 'The Useful Native Plants of Australia' notes of A. elongatus that 'The tuberous roots of these water-plants are starchy, and of excellent taste, though not large'. The Madagascar lace plants (A. madagascarensis) require special handling as they prefer cooler water – 70 °F (21 °C) as a maximum.

Reader's Guide

Aponogeton holds significance as a genus of aquatic plants widely used in aquariums and ponds, with several species cultivated for ornamental purposes. The article notes that all Aponogeton species are easy to grow when their preferences are met. African species, with the exception of A. rigidifolius (which has a rhizome), experience a natural rest period corresponding to their habitat drying out. Asian species may also have a rest period related only to temperature. During rest, the plant can be taken out and put in a bowl of damp sand in a dark, cool place for 2–3 months at 50–64 °F until small leaves sprout.

Several Madagascan species have been introduced as new aquarium plants in the early 21st century, including A. boivinianus, A. longiplumulosus, A. madagascariensis, and A. ulvaceus. From Asia and Australia, A. crispus, A. elongatus, A. rigidifolius, A. robinsonii, and A. undulatus are useful aquarium plants. The tubers of several species are eaten by humans and livestock. The annual export of thousands of dormant A. crispus specimens shipped in a totally dry state exploits the tubers' high resistance to drying out. As of 2010, Australian species exist in very small numbers in the hobby trade.

Did You Know?

• The oldest known Aponogeton fossils are pollen from the Late Cretaceous of Wyoming, about 82-84 million years old.
• African Aponogeton species generally have multiple blooming stems on the same flower stalk, while Asian species have a single bloom stalk.
• The tubers of several Aponogeton species are eaten by humans and their livestock.