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Achyranthes aphylla

Interesting Facts

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Description

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Family Amaranthaceae

Herbs, clambering subshrubs , shrubs , or lianas. Leaves alternate or opposite, entire, exstipulate . Flowers small, bisexual or unisexual , or sterile and reduced, subtended by 1 membranous bract and 2 bracteoles, solitary or aggregated in cymes. Inflorescences elongated or condensed spikes (heads ), racemes , or thyrsoid structures of varying complexity. Bracteoles membranous or scarious . Tepals 3-5, membranous, scarious or subleathery, 1-, 3-, 5-, or 7(-23) -veined. Stamens as many as tepals and opposite these, rarely fewer than tepals; filaments free , united into a cup at base or ± entirely into a tube , filament lobes present or absent, pseudostaminodes present or absent; anthers (1- or) 2-loculed, dorsifixed , introrsely dehiscent . Ovary superior, 1-loculed; ovules 1 to many; style persistent , short and indistinct or long and slender; stigma capitate, penicillate , 2-lobed or forming 2 filiform branches. Fruit a dry utricle or a fleshy capsule, indehiscent, irregularly bursting, or circumscissile. Seeds lenticular , reniform , subglobose, or shortly cylindric , smooth or verruculose .

About 70 genera and 900 species: worldwide; 15 genera (one introduced ) and 44 species (three endemic, 14 introduced) in China.

Morphology of the androecium, perianth (tepals), and the inflorescence has traditionally been used to circumscribe genera and tribes . Pseudostaminodia are interstaminal appendages with variously shaped apices. Filament appendages are the lateral appendages of filaments (one on each side) . The basic structure of the inflorescence is the cyme (branchlets arising from the bracteole axils, the bracteoles serving as bracts for upper flowers), which can be reduced to one flower with two bracteoles and a bract. Units of dispersal vary considerably (capsules opening with lower part persistent, flower and bracteoles falling together, or cymose partial inflorescences breaking off above bract) and can be characteristic for genera. Several genera possess long trichomes serving dispersal at the base of the tepals.[1]

Genus Achyranthes

Herbs, perennial or annual . Stems erect to ascending . Leaves opposite, petiolate ; blade elliptic , ovate to orbiculate, or broadly rhombate, margins entire. Inflorescences terminal and axillary , pedunculate , elongate , many-flowered, simple spikes or few-branched panicles; flowers crowded together at tips , becoming more widely spaced toward base . Flowers bisexual , often becoming deflexed with age; tepals 4 or 5, basally connate , without ornamentation, coriaceous , becoming indurate in fruit, ± glabrous ; filaments basally connate into short tubes or cups ; anthers 4-locular; pseudostaminodes 5; ovary obovoid or turbinate ; ovule 1; style elongate; stigma 1, capitate. Utricles enclosed by and falling with indurate tepals, elliptic or cylindric , membranous, indehiscent. Seeds 1, inverted , obovoid or ovoid , smooth .

Species 8-12: c and se United States, Mexico, West Indies, Central America, South America, tropical , subtropical , and warm-temperate regions of the Old World.

The groups of plants referred to as Achyranthes and Alternanthera have been subject to considerable nomenclatural confusion, primarily because P. C. Standley (1915) designated Achyranthes repens Linnaeus as the lectotype species of Achyranthes. As a result, species that had been placed in Achyranthes were transferred to Centrostachys Wallich, and species that had been in Alternanthera were transferred to Achyranthes. A. A. Bullock (1957; see also R. Melville 1958) showed that Standley's lectotypification was incorrect and that the type species of Achyranthes is Achyranthes aspera Linnaeus. The generic concepts of Achyranthes and Alternanthera then returned to those prior to 1915.[2]

Taxonomy

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Synonyms

Alternanthera aphylla Glaz.

Notes

Publishing author : Standl. Publication : J. Wash . Acad. Sci. 5: 74 1915

Similar Species

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Members of the genus Achyranthes

ZipcodeZoo has pages for 14 species, subspecies, varieties, forms, and cultivars in this genus:

A. amaranthoides (Jiang Guo Xian) · A. aspera (Devil's Horsewhip) · A. aspera var. aspera (Devil's Horsewhip) · A. aspera var. pubescens (Devils Horsewhip) · A. atollensis (Hawai'i Chaff Flower) · A. bidentata (Niu Xi) · A. japonica (Japanese Chaff Flower) · A. japonica var. hachijoensis (Japanese Chaff Flower) · A. lanuginosa (Woolly Tidestromia) · A. mutica (Blunt Chaff Flower) · A. splendens (Maui Chaff Flower) · A. splendens rotundata var. rotundata (Maui Chaff Flower) · A. splendens var. rotundata (Round Chaff Flower) · A. splendens var. splendens (Maui Chaff Flower)

More Info

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Further Reading

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Notes

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Contributors

Identifiers

Footnotes

  1. Bojian Bao, Thomas Borsch & Steven E. Clemants "Amaranthaceae". in Flora of China Vol. 5 Page 415. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. Kenneth R. Robertson "Achyranthes". in Flora of North America Vol. 4 Page 406, 435. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 2012-07-27