The genus Lagenandra is a group of medium- to small-sized aroids found in tropical Asian countries such as Sri Lanka and India. Lagenandra species have been grown and distributed by tropical fish and aquarium hobbyist around the world, but this group is still uncommon in most stores and only specialty stores may carry it.
I have found that, like many aquatic or bog plants sold in the aquarium business, it is not uncommon for aroids to be unable to reach their true potential when constantly submerged under water. In their natural habitat many aquatic or bog type aroids will only flower once the water level is low enough for the flowers to reach the air for insects to pollinate. This is why many aquarium aroids such as cryptocoryne and lagenandra rarely if ever flower underwater in aquariums.
Lagenandra ovata is a larger grower commonly found on creek beds and usually only submerged totally during flooding. Growing to 1 to 3 feet tall, the leaves are paddle-shaped held on a 1 to 2 foot petiole. One of the main distinctive features of Lagenandra that separate it from the group Cryptocoryne is the fact that the leaves unfurl involute, which means each side of the leaf rolls out like an ancient scroll from the midrib. The inflorescences of this plant are equally interesting and unique. They are formed near the growth tip along the crawling rhizome, with a single inflorescence emerging from between the growth tip and the last petiole. These are oddly shaped, usually dark purple to almost black in color, and are around 6 to 8 inches long depending on maturity of the plant. The inflorescence has the usual aroid components of a spathe surrounding the actual flowers on the spadix, but the spathe reminds me of an upside-down conch sea shell and is constructed in a similar shape. This odd twisted shape and small chambers may help the plant keep the spadix and flower structures secure and dry if flooded or submerged.
The spadix is oddly shaped when compared to other aroids I have seen in the past. The female flowers are located at the base of the spathe as a cluster or small mound with receptive stigmas ready for pollen. Emerging from the top of the female section is a very narrow and skinny non-fertile structure at the top of which is a wider fertile male section. Lagenandra was not self-pollinated under my conditions but the shape of the spathe may make it possible for this to occur if the male and female zones are producing pollen and receptive at the same time.
I have found that for me the plant performs best in a tray or shallow water area. My water is heated to 65°F minimum and up to 90°F maximum. I often add nutrients to the water in low doses; in most cases 10% of the recommended dosage called for on a regular liquid feed (that is 1 to 2 pinches of the fertilizer per gallon of water).
Overall Lagenandra ovata is a fine plant but many collectors tend to overlook these great aquatic aroids due to their water requirements and tender nature. I have found that for me in the cold winter months in the north, small to medium aquatic aroids have proved to be entertaining and interesting. I am able to grow a large number of unique species in a small area and the results have been very rewarding. The possibilities for such plants have potential as great additions to tropical ponds in warm climates or greenhouse plants grown in water-filled trays, as well as to the at home hobbyist growing them in aquariums and terrariums. It has been obvious that with attention to just a few requirements they can be real botanical treasures to grow.
Fig. 1. Lagenandra ovata.
Lagenandra ovata. Inflorescence
Fig. 2. Lagenandra ovata. Inflorescence dissected
Fig. 3. Plants growing in tray of shallow water