Common names
Pygmy chain sword plant
 |
| Echinodorus tenellus |
image source: http://www.flickr.com/photos/clearlydived/
Synonyms
Alisma tenellus Martius; Alisma tenellum; Echinodorus naine; Echinodorus parvulus Engelm.; Echinodorus tenellus var. ecostatus; Echinodorus tenellus (Mart.) Buch. var. latifolius (Seub.) Fassett; Echinodorus tenellus (Mart.) Buch. var. parvulus (Engelm.) Fassett; Helianthium parvulum (Engelm.) Britt.; Helianthium tenellum Britt.; Sagittaria microfolia.
Distribution
Echinodorus tenellus is found throughout North, Central, and South America, especially in Southern Brazil and the southern states of North America. It may be the widest-distributed of all the Echinodorus, with the most northerly range.
There may be several different variations, which have at times been given separate taxonomic rank.
It is only rarely found in running water. Normally it is found in wet sand on the shores of pools or in inundated zones of rivers.
There may be several different variations, which have at times been given separate taxonomic rank.
It is only rarely found in running water. Normally it is found in wet sand on the shores of pools or in inundated zones of rivers.
Description
The leaves of E. tenellus are narrowly elliptical or lanceolate. At different times during the plant's life cycle, the blade of the leaf is scarcely distinguishable from the petiole, while at other times the petiole is 10 to 15 times as long as the blade, which may be 1-4 cm long and 0.2-1 cm wide, with a pointed tip. The base is decurrent to the petiole and has between one and three veins.
The stem is thin, erect, often curved and radicans, and may be 3-20 cm long. In small plants, the stem ends in a single inflorescence (umbel or coil); in larger plants the inflorescence is racemose, composed of two whorls placed one above the other. Bracts are free and 2-6 mm long in the first whorl. Pedicels are 1-3.5 cm long. Sepals are 3 mm long, membraneous, and usually have five fine ribs. During ripening, the sepals enlarge and reach a length of up to 6 mm and fully cover the aggregate fruit. A specimen may have six to nine stamens, each about 1 mm long. Anthers are 0.25 mm wide by 2.25 mm long, which is three times shorter than the filaments. It may have sixteen to eighteen pistils. The achenes are compressed, and arched in the apical part; they are (0.9) - 1.1 - (1.3) mm long, and black, with three lateral ribs. The basis of the stylar beak is under the level of the tip of the nutlet and may be 0.1-0.3 mm long.
It is a highly variable species according to its geography and environmental conditions.
The stem is thin, erect, often curved and radicans, and may be 3-20 cm long. In small plants, the stem ends in a single inflorescence (umbel or coil); in larger plants the inflorescence is racemose, composed of two whorls placed one above the other. Bracts are free and 2-6 mm long in the first whorl. Pedicels are 1-3.5 cm long. Sepals are 3 mm long, membraneous, and usually have five fine ribs. During ripening, the sepals enlarge and reach a length of up to 6 mm and fully cover the aggregate fruit. A specimen may have six to nine stamens, each about 1 mm long. Anthers are 0.25 mm wide by 2.25 mm long, which is three times shorter than the filaments. It may have sixteen to eighteen pistils. The achenes are compressed, and arched in the apical part; they are (0.9) - 1.1 - (1.3) mm long, and black, with three lateral ribs. The basis of the stylar beak is under the level of the tip of the nutlet and may be 0.1-0.3 mm long.
It is a highly variable species according to its geography and environmental conditions.
Cultivation
Easy to grow in tropical aquariums or outside in and around ponds in warmer regions. It will form a mat in good conditions and in plenty of light. Likes a good substrate of small grained gravel / sand. Benefits from additional CO2. Ideal for the fore - mid-ground of the aquarium. Will tolerate lower temperatures than many other Echinodorus, down to at least 68F (20C) or lower. Propagates readily by runners.
