Talk:Hymenachne amplexicaulis

Wiki Education Foundation-supported course assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 7 January 2019 and 24 April 2019. Further details are available on the course page. Student editor(s): Kquincy.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 22:44, 17 January 2022 (UTC)

Comments from Emily
[Really nice looking page!]

Does "hymenachne" mean anything? I find it interesting that this is essentially the common name. It's unusual that something so Latin/Greek sounding would also be used as the common name, so it would be useful to know the etymology, and to have that up at the top, in the header paragraph.

Hymenachne amplexicaulis, also known as West Indian marsh grass in the US, Olive hymenachne in Australia, and hereafter referred to as hymenachne, is New World species in the genus Hymenachne. This freshwater species is native to the tropical and subtropical regions of the West Indies, Northern South America, and Central America.

Biology
Hymenachne is a perennial grass that primarily reproduces via stolons. This robust species is commonly found growing 1-2.5m tall. The stems are hairless and float prostrate across the top of the water, then grow upright from these bases to support leaves. The flat, triangular leaves (10–45 cm long, up to 3 cm wide) have a [remove] prominent clasping bases, or auricles. The auricles help to distinguish it from other invasive wetland grasses and the native H. acutigluma in Australia [What does prominent mean in this case? Also, do the other invasive and native plants not have prominent clasping bases? I only say this because I just finished keying out plants where some descriptions highlighted a distinguishing feature that is prominent within the genus, but the particular species of interest was "more" prominent than the others]Ted Salad (talk) 02:37, 2 April 2019 (UTC) Hymenachne has been shown to increase the stem length between nodes to keep leaves above water during periods of flooding. Its stem is packed with airy tissue called aerenchyma [I would link this and any other descriptive plant terminology that may be gibberish to non-botanists]Ted Salad (talk) 02:37, 2 April 2019 (UTC)to help the stems float and to aid in flood tolerability.

Hymenachne flowers in the early fall and sets seeds in late fall. The flower [panicles are inflorescences, not flowers, and panicle should have a link to its wikipedia page] is a panicle that can grow to half a meter. Researchers at the University of Florida have seen multiple panicles per plant originating from branching at a single node. Hymenachne can produce thousands of seeds with up to 98% germination right off the panicle.

Habitat
Hymenachne prefers constantly inundated soil and is known to survive comfortably in about a meter of water for 20 years. This species was shown to survive poorly in Australia where flooding exceeded 1.2 m. In its native range in Venezuela, and in invaded areas of Florida, hymenachne was documented to survive in >1.2m of water for nearly a year. Hymenachne has also been found in water greater than 4m deep persisting in floating mats, likely dislodged after a storm event. Conversely, hymenachne is not recorded to survive sites that entirely dessicate.

Hymenachne is known to colonize and form dense monocultures in floodplains, roadside ditches, and lake margins in invaded and native areas. It is often found colonizing areas with little shading and competition from other species. Although limited information is available on soil preferences of hymenachne, it has been found in deep, poorly drained muck soils in Florida. It is not found in waters with a significant salt concentration.

Invasion
There have been three introductions of hymenachne into Australia, one in [to] Florida, and one in [to] Louisiana. Australia now lists hymenachne as one of the top twenty worst weeds. Hymenachne invasions have been shown to decrease species richness, increase invasive fish populations, and overall cause fundamental changes in floral and faunal composition in Australia[Do we know how? You mentioned above it does well in areas with less competition. So, how does it displace species and reduce species richness?]Ted Salad (talk) 02:53, 2 April 2019 (UTC). Hymenachne was introduced in Australia as forage for cattle, and likely for the same reason in Florida. The species was used in ponded pastures, or artificial ponds created to hold water for use in the dry season. High reproducibility from stem fragments aids in the dispersal and invasion of this species. [Is it wind dispersed?]Ted Salad (talk) 02:53, 2 April 2019 (UTC) The first herbarium record of hymenachne in Florida is from 1957. The second specimen is not recorded until 1977. The cause for this gap is unknown; however, today it is recorded in 28 counties across the state.