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Echinodorus major in flower

Discussion in 'Plant Identification & Biology' started by Byron, Apr 30, 2017.

  1. Byron

    Byron Member

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    Some of the most beautiful and useful plants for the tropical aquarium are found among the Echinodorus, a genus distributed in the tropical and sub-tropical regions of the Americas from the lower United States down to Argentina; the two "African" species of Rataj are erroneous (Kasselmann, 2003; Lehtonen 2008). Echinodorus derives from the Greek echinos [hedgehog] and doros [pipe or hose] referring to the spiny fruit. The English common name of "sword plant" comes from the general lanceolate shape of the leaf of most species and is generally used for all plants in this genus although other non-Echinodorus plants may sometimes appear under the name "sword."

    Nomenclature within this genus is confusing, and the plethora of hybrids within the aquarium hobby has not helped. Rataj (1975) listed 47 species, while the botanists R.R. Haynes and L.B. Holm-Nielsen (1994) listed 26 species. In his 2004 revision, Rataj increased the number of species to 62. More recent work by Samuli Lehtonen—incorporating phylogenetic (DNA) analysis—proposed 28 valid species (Lehtonen, 2007). As of 2013, The Plant List and the World Checklist of Selected Plant Families (maintained by Kew) have 30 distinct species (two newly described in addition to Lehtonen) listed for Echinodorus. There is still a lot of confusion with the many hybrids (Lehtonen, 2016).

    One of the most attractive species, due to its undulating leaves, is the commonly-named Ruffled Amazon Sword. Some authors list this species as Echinodorus martii (Micheli, 1881) but Lehtonen (2008) determined the correct species is Echinodorus major (Micheli) Rataj, 1967. Unlike most species in the genus which are bog plants, growing emersed for half the year and submersed during the rain/wet season, this plant grows permanently submersed in its South American habitats. The inflorescence thus flowers during submersed growth, something that does not occur with the amphibious bog species which only flower during the emersed period of growth. Adventitious plants, but rarely if ever flowers, occur along the inflorescence when the plant is grown permanently submersed in the aquarium.

    My original plant, acquired in 2008, flowered in 2010, but not again until today. Inflorescences are few on this species; this is only the second time one has appeared, whereas my Echinodorus grisebachii (var. bleheri) send out anywhere from one up to five inflorescences once and sometimes twice each year. As those plants are grown submersed, flowers have never appeared, only many adventitious plants.

    Here are some photos I took this morning after the water change, when I discovered the inflorescence and flowers. This time, as was the case in 2010, the inflorescence wound its way around other plants to the surface, and the tip above the water is flowering.

     

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  2. Tyler_Fishman

    Tyler_Fishman Fish Crazy

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    Is the the term "Var." short for variation? I see this used in the Anubias sp. as well, such as Anubias Bateri Var. Nana.
     
  3. DutchMuch

    DutchMuch Fish Addict

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    Variety or variation yes
     
  4. Byron

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    "Var." in scientific nomenclature is the abbreviation for varietas, the Latin word translated into the English word variety. "Variation" is not an accurate meaning, as it implies something quite different. A variation of a species is something that varies in some way, whereas a variety holds a specific and distinct set of differences that are constant. A variety could eventually lead to a subspecies or even distinct species from the original, whereas a variation does not.

    The "Var." is not a scientific designation, i.e., not part of the scientific nomenclature, but a common name to set apart something that has those specific characteristics that make it different from the species. In the case of Echinodorus grisebachii var. bleherae for example, the species is E. grisebachii. The "Var. bleherae" shows that there is a group of plants in this species that have different characteristics from the norm, but not sufficiently to indicate a distinct subspecies or species. Rataj (1970) described a species Echinodorus bleherae, and for years this has been the "common" Amazon Sword in aquaria.

    Haynes & Holm-Nielsen (1994) considered the species E. bleherae, E. amazonicus and E. parviflorus to be conspecific [the same species] with E. grisebachii. The phylogenetic analysis (Lehtonen, 2008, et al.) has verified their surmise, since all these plants have the same DNA. Once this is determined, under the rules of scientific nomenclature the species epithet that must be assigned to the distinct species is the name first used to designate a specimen of that species as distinct. As E. grisebachii was the first name used by the botanist J.K. Small in 1909 to designate the specimen plant, this is the accepted name of this distinct species, which to be correct is written as: Echinodorus grisebachii Small, 1909. The subsequent names E. bleherae, E. amazonicus, E. parviflorus, etc. become what we term synonymns to show that they refer to the same distinct species E. grisebachii.

    An aside: We use binomial nomenclature to identify all species of plant and animal on earth. There are normally two parts to a species name, the genus (often Greek, sometimes Latin) and the species epithet (always Latin). The genus may change, sometimes many times, as scientists determine new relationships; example, the Serpae Tetra has been classified in five different genera, now accepted since Weitzman & Palmer (1997) as Hyphessobrycon eques (Steindachner, 1882). But the species epithet never changes fro that first applied to a specimen of that species, so this remains constant--except when later found to be in error, for example someone designating a specimen of a species as a new species and thus giving that specimen a new name. When this occurs, the oldest name must prevail; there are one or two exceptions even to this, but minor and not relevant for our purposes. The parenthesis around the describers name and date indicates that the genus has changed since that ichthyologist first described the fish as a distinct species. Credit for the description and naming of a species is always given to the first person who recognized it as distinct, regardless of how many subsequent changes.

    This can be seen in fish species too.

    Carnegiella strigata is the Marble Hatchetfish. There are two externally different varieties that are geographical. A geographical variety means that the differences are unique to those fish in the same general geographical area, which is usually (in the case of fish) a river basin or sometimes even just a particular river or stream. The pattern on the population from British Guyana is black, and the wide mid-thorax band divides approximately in the middle of the band. The pattern on the population from the Peruvian Amazon has a brownish-black pattern, and the mid band divides right at the anterior edge of the thorax. There are populations of both in the Rio Negro basin, but they remain separate so far as is known.

    At one time or another, five species of marble hatchetfish were recognized, reorganized into two by Weitzman (1960), C. strigata and C. vesca. Gery (1977) recognized the very close physiological structure and modified these into subspecies as C. strigata strigata and C. strigata fasciata respectively, and noted that all species in this genus are polytipic, meaning that two or more distinct populations can be recognized within the species concepts of C. strigata, C. marthae, and C. myersi. Weitzman & Palmer in Reis, et al. (2003) consider the one single species C. strigata and this is the accepted nomenclature at present. To my knowledge, phylogenetic analysis has not yet occurred with this species, so when that is carried out, there may be two sub-species, two distinct species, or one distinct species with geographical variants.

    Byron.
     
    #4 Byron, May 2, 2017
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  5. Tyler_Fishman

    Tyler_Fishman Fish Crazy

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    Thanks, very informative
     
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  6. Tyler_Fishman

    Tyler_Fishman Fish Crazy

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    My E. Parvifolious sent up an inflorescence, it’s quite happy in the corner which is where it receives direct sunlight for about 2 hours each day (depending on weather though). I know that the inflorescence can produce tiny plantlets as an asexual means of reproduction, which I would prefer, do the flowers self pollinate? If so I would not want to miss out on getting plantlets if it does not go to seed, but I also don’t want to miss out on a flowering event, my other question is will it produce plantlets with flowers?
     
  7. Byron

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    I'm not sure if you are saying you have flowers or not, but this "species" is not likely to actually flower if grown permanently submersed. My plants developed adventitious plants from the nodes along the inflorescences, which is the norm for Echinodorus species when grown submersed, with the exception of E. major that will flower and produce adventitious plants; other species in the genus tend to only produce flowers when grown emersed as bog or marsh plants, as they would in their habitats. So you should see the adventitious plants; when they have some roots and leaves they can be separated from the inflorescence (they no longer obtain nutrients via the inflorescence at this point), or left.

    There is no natural species E. parviflorus; the plant that Rataj (1970) described as Echinodorus parviflorus has been shown by phylogenetic analysis to be a variety of E. grisebachii. I wrote about this in post #4 above. The plant seen in stores as "E. parviflorus" is more correctly named "Echinodorus parviflorus var. Tropica." The Tropica nurseries in Denmark developed this form from the wild plant (thought to be E. parviflorus) and it has very dark green thick and hammered leaves. It is a lovely plant.
     
  8. Tyler_Fishman

    Tyler_Fishman Fish Crazy

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    No doubt it’s a nice little sword plant, the spike seems to be reaching the surface however, unlike my E.cordifolious, who’s spike simply bent and grew plantlets in the water. No plantlets yet just developing buds.
     
  9. Byron

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    If memory serves me, the inflorescences that appeared on my "parviflorus" were very slow growing compared to those I have regularly on my E. major and E. grisebachii (bleherae). And they came no where close to the surface as the plants then were in a deep tank. But adventitious plants did develop.
     
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  10. thrujenseyes

    thrujenseyes Member

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    Wow Byron that must be so satisfying and amazing to witness. How very cool and beautiful!
    Thanks for sharing :)
     
  11. Colin_T

    Colin_T Member

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    I had an amazon swordplant growing in a pot in some potting mix in the garden. I had a tray under the pot and it lived out in full sun all year round. When it was 1 year old it sent out a flower stalk about 4 ft long. It also produced a second plant, which grew next to the original. The following year they both produced a number of flower stalks that reached about 6 ft long. Each year after that there were flower spikes all summer and flowers and seed everywhere. The only thing I did for the plant was fertilise it with Thrive liquid plant fertilise once a week, and water them when the tray is dry.
    You can keep them like any normal garden plant, same with Crypts and Hygrophillas.
     

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