''Echinodorus horizontalis'' is a species of plant in the

Alismataceae The water-plantains (Alismataceae) are a family of flowering plants, comprising 19 genera (17 extant and 2 fossil) and 117 species. The family has a cosmopolitan distribution, with the greatest number of species in temperate regions of the Northe ...

family. It is native to northern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

(

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in ...

, Colombia, Guyana,

Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

, northern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Description

The leaves are 25 – 40cm long. The blades join the petiole at an obtuse angle so that they stand nearly horizontally. They are ovate or cordate, on the tip acuminate, the base truncate or shortly lobate, usually with 7 veins, 10 – 17cm long x 5 – 8cm wide. Stem recurved, proliferous, 25 – 60cm long. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed ...

is racemose, having 2 – 4 whorls containing only 3 – 6

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

each. The bracts are shorter than pedicels, which are 1 – 1.5cm long. The

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

are ovate, membraneous, 4 – 6mm long, having 18 – 24 ribs. During ripening the sepals enlarge and cover partly the aggregate

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

. The

petals Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...

are white, ovate,

corolla Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name * Corolla (headgear), an ancient headdress in the form of a circlet or crown * ''Corolla'' (gastropod), a genus of moll ...

1.5 – 1.8cm in diameter,

stamens The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

26 – 30cm.

Anthers The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

oblong, 5 – 10 x shorter than filaments. The aggregate

is globular, 0.7 – 0.9cm in diameter,

achenes An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not op ...

3mm long x 1mm wide, having 3 – 4 ribs and usually 6 glands in 2 rows. Young leaves are red and brown, while older leaves are green.

Cultivation

The plant needs a deep bed of rich substrate, and plenty of light and water on the more acidic and soft side, and tropical temperatures. It will grow well emersed or submersed. Propagation is mainly by adventitious plantlets, which form on the inflorescence. A rather demanding species, it is now rarely seen. The flowers, normally emersed, open in the later morning hours only for about 2 hours. After this, it closes completely. ''E. horizontalis'' opens its flowers even under water. The plant is self-fertile. Seed germination seems variable, but Rataj & Horemann report most success at higher temperatures (28 C). Without flowers it can be confused with other species such as ''E. tunicatus'', and rarely seems to be offered as the true species in the trade.

References

External links

''Echinodorus'' site
horizontalis Plants described in 1969 Flora of Colombia Flora of Guyana Flora of Ecuador Flora of Peru Flora of Brazil Flora of Venezuela Freshwater plants {{alismatales-stub