bio.wikisort.org - Plant

Helanthium tenellum, the pygmy chain sword, is a species of plants in the Alismataceae. It is native to the eastern United States (from Texas to Florida, north to Michigan and Massachusetts), southern Mexico (Chiapas, Veracruz), West Indies (Cuba, Jamaica, Hispaniola), Central America, South America (from Guyana to Argentina)[1][2]

Helanthium tenellum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Alismatales
Family:	Alismataceae
Genus:	Helanthium
Species:	H. tenellum
Binomial name
Helanthium tenellum (Mart. ex Schult.f.) J.G.Sm.
Synonyms[1]
Alisma tenellum Mart. ex Schult.f. in J.J.Roemer & J.A.Schultes Echinodorus tenellus (Mart. ex Schult.f.) Buchenau Sagittaria tenella (Mart. ex Schult.f.) Kuntze Alisma ranunculoides var. brasiliense A.St.-Hil. Echinodorus parvulus Engelm. in A.Gray Echinodorus subulatus Engelm. in A.Gray Helanthium parvulum (Engelm.) Small in N.L.Britton & al. Echinodorus tenellus var. ecostatus Fassett Echinodorus tenellus var. parvulus (Engelm.) Fassett Echinodorus tenellus f. randii Fassett

Description

The leaves of H. tenellum 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 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.[3][4]

It propagates by sending out runners and will also flower when grown emersed.[5]

Conservation status in the United States

It is endangered in Connecticut,[6] Illinois, Indiana, Kentucky, and Michigan.[7]

In the aquarium

Helanthium tenellum is a common aquarium plant with a large variation in shapes and sizes kept by people for their aesthetic appeal. Its care is undemanding and it can adapt to a large range of conditions.[5]

References

External links

• Photo of herbarium specimen collected in Missouri in 1845, Helanthium tenellum
• Flora of North America, Echinodorus tenellus
• US Department of Agriculture plant profile, Echinodorus tenellus
• Mary-Ann Lambert, Natura, Les Plantes aquatiques, Echinodorus tenellus
• Flora of Missouri, Echinodorus tenellus
• AquaHobby, The Age of Aquariums, Echinodorus tenellus
• Krib discussions

На других языках

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- [en] Helanthium tenellum

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[es] Helanthium tenellum

El cucharero (Helanthium tenellum) es una especie de la familia de la papa de agua (Alismataceae), dentro del orden Alismatales en lo que comúnmente llamamos grupo de las monocotiledóneas, aunque hoy en día se agrupan dentro del grupo Liliopsida. El nombre del género Echinodorus se deriva del griego “echinos” (puerco espín) y “doros” (bolsa o botella), haciendo referencia a los aquenios espinosos, la especie, E. tenellus, hace referencia a su hábito, pequeño, delicado o tierno.[1]

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[ru] Эхинодорус нежный

Эхинодо́рус не́жный (лат. Echinodorus tenellus) — травянистое растение рода Эхинодорус семейства Частухоцветные, известное среди аквариумистов также как «карликовая амазонка».

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