The species of Heterostachys grow as subshrubs or low shrubs. The stems are much branched, glabrous, and not jointed. The alternate leaves are fleshy, glabrous, scale-like, stem-clasping, with very short free blades (1–2 mm).[1]
The inflorescences are orbicular to cone-like, with alternate to nearly opposite scale-like bracts, and with one free flower sitting in the axil of each bract. The flowers are bisexual. The four-lobed perianth consists of four half-connate unequal tepals. There are two stamens and an ovary with two stigmas.[1]
In fruit the perianth becomes thick and spongy. The fruit wall (pericarp) is membranous. The seed is lenticular to edge-shaped with tuberculate surface. It contains a semi-annular embryo and copious perisperm (feeding tissue).[1]
The genus Heterostachys was first published in 1876 by Franz Ungern-Sternberg.[3] With this description, he replaced the invalid name Spirostachys Ung.-Sternb. from 1866,[4] (which is illegitimate, as Spirostachys Sond. already existed since 1850). The type species is Heterostachys ritteriana.[5]
Heterostachys is closely related to the genus Allenrolfea, which also is distributed in America. Their common lineage seems to have evolved early in the evolution of the subfamily Salicornioideae, dating back to the Early to Middle Oligocene. It might have reached America long before the other American taxa of Salicornioideae.[1]
Referencesedit
^ abcdefgGudrun Kadereit, Ladislav Mucina & Helmut Freitag: Phylogeny of Salicornioideae (Chenopodiaceae): diversification, biogeography, and evolutionary trends in leaf and flower morphology, In: Taxon, Volume 55 (3), 2006, p. 623, 624, 632.
^ abTropicos, specimen list for Heterostachys ritteriana (Moq.) Ung.-Sternb.
^Franz Ungern-Sternberg: Salicorniearum Synopsis. In: Atti del congresso internazionale botanico tenuto in Firenze nel mese di maggio 1874, 1876, p. 331. first publication of Heterostachys
^Franz Ungern-Sternberg: Versuch einer Systematik der Salicornieen, Inaug. Diss., Dorpat: Karow., 1866, p. 100. first publication of Spirostachys Ung.-Sternb..
^F.O. Zuloaga, O. Morrone, M.J. Belgrano, C. Marticorena, E. Marchesi. (Hrsg.) 2008. Catálogo de las plantas vasculares del Cono Sur. Monogr. Syst. Bot. Missouri Bot. Gard. 107(1–3): i–xcvi, 1–3348. Heterostachys olivascens.
^F.O. Zuloaga, O. Morrone, M.J. Belgrano, C. Marticorena, E. Marchesi. (Hrsg.) 2008. Catálogo de las plantas vasculares del Cono Sur. Monogr. Syst. Bot. Missouri Bot. Gard. 107(1–3): i–xcvi, 1–3348. Heterostachys ritteriana.
External linksedit
Media related to Heterostachys at Wikimedia Commons
Data related to Heterostachys at Wikispecies
Illustration of Heterostachys olivascens at Instituto de Botanica Darwinion.
[1], [2], [3] Illustrations of Heterostachys ritteriana at Instituto de Botanica Darwinion.
January 01, 1970
heterostachys, genus, flowering, plants, plant, family, amaranthaceae, species, shrubby, halophytes, native, south, america, central, america, olivascens, scientific, classification, kingdom, plantae, clade, tracheophytes, clade, angiosperms, clade, eudicots, . Heterostachys is a genus of flowering plants in the plant family Amaranthaceae The two species are shrubby halophytes native to South America and Central America Heterostachys Heterostachys olivascens Scientific classification Kingdom Plantae Clade Tracheophytes Clade Angiosperms Clade Eudicots Order Caryophyllales Family Amaranthaceae Subfamily Salicornioideae Genus HeterostachysUng Sternb Species Heterostachys olivascens Speg Molfino Heterostachys ritteriana Moq Ung Sternb Contents 1 Description 2 Distribution and habitat 3 Systematics 4 References 5 External linksDescription editThe species of Heterostachys grow as subshrubs or low shrubs The stems are much branched glabrous and not jointed The alternate leaves are fleshy glabrous scale like stem clasping with very short free blades 1 2 mm 1 The inflorescences are orbicular to cone like with alternate to nearly opposite scale like bracts and with one free flower sitting in the axil of each bract The flowers are bisexual The four lobed perianth consists of four half connate unequal tepals There are two stamens and an ovary with two stigmas 1 In fruit the perianth becomes thick and spongy The fruit wall pericarp is membranous The seed is lenticular to edge shaped with tuberculate surface It contains a semi annular embryo and copious perisperm feeding tissue 1 Distribution and habitat editHeterostachys is distributed in South America and Central America Hispaniola 1 2 The plants are halophytes and grow in coastal lagoons and salty inland habitats 1 Systematics editThe genus Heterostachys was first published in 1876 by Franz Ungern Sternberg 3 With this description he replaced the invalid name Spirostachys Ung Sternb from 1866 4 which is illegitimate as Spirostachys Sond already existed since 1850 The type species is Heterostachys ritteriana 5 The genus comprises two species 1 Heterostachys olivascens Speg Molfino endemic to Argentina Buenos Aires Mendoza Rio Negro at 0 500 m above sea level 6 Heterostachys ritteriana Moq Ung Sternb widely distributed in South America and Central America Argentina Paraguay Venezuela Peru Haiti Dominican Republic 7 2 Heterostachys is closely related to the genus Allenrolfea which also is distributed in America Their common lineage seems to have evolved early in the evolution of the subfamily Salicornioideae dating back to the Early to Middle Oligocene It might have reached America long before the other American taxa of Salicornioideae 1 References edit a b c d e f g Gudrun Kadereit Ladislav Mucina amp Helmut Freitag Phylogeny of Salicornioideae Chenopodiaceae diversification biogeography and evolutionary trends in leaf and flower morphology In Taxon Volume 55 3 2006 p 623 624 632 a b Tropicos specimen list for Heterostachys ritteriana Moq Ung Sternb Franz Ungern Sternberg Salicorniearum Synopsis In Atti del congresso internazionale botanico tenuto in Firenze nel mese di maggio 1874 1876 p 331 first publication of Heterostachys Franz Ungern Sternberg Versuch einer Systematik der Salicornieen Inaug Diss Dorpat Karow 1866 p 100 first publication of Spirostachys Ung Sternb Heterostachys Tropicos Missouri Botanical Garden F O Zuloaga O Morrone M J Belgrano C Marticorena E Marchesi Hrsg 2008 Catalogo de las plantas vasculares del Cono Sur Monogr Syst Bot Missouri Bot Gard 107 1 3 i xcvi 1 3348 Heterostachys olivascens F O Zuloaga O Morrone M J Belgrano C Marticorena E Marchesi Hrsg 2008 Catalogo de las plantas vasculares del Cono Sur Monogr Syst Bot Missouri Bot Gard 107 1 3 i xcvi 1 3348 Heterostachys ritteriana External links edit nbsp Media related to Heterostachys at Wikimedia Commons nbsp Data related to Heterostachys at Wikispecies Illustration of Heterostachys olivascens at Instituto de Botanica Darwinion 1 2 3 Illustrations of Heterostachys ritteriana at Instituto de Botanica Darwinion Retrieved from https en wikipedia org w index php title Heterostachys amp oldid 1134129353, wikipedia, wiki, book, books, library,
![[1]](http://www2.darwin.edu.ar/ImagenesIris/Heterostachys%20ritteriana_INTA_F%20ARG.jpg){kind=link}
![[2]](http://www2.darwin.edu.ar/ImagenesIris/Heterostachys%20ritteriana_CORD.jpg){kind=link}
![[3]](http://www2.darwin.edu.ar/ImagenesIris/Heterostachys%20ritteriana01_SI.jpg){kind=link}