On the Horizon: Generic changes for the amaranth family
- Tim Hammer
- Mar 28, 2019
- 2 min read
The amaranth family (Amaranthaceae) are flowering plants with a cosmopolitan distribution. You may be familiar with some of the species used in agriculture (e.g. grain amaranth or Amaranthus species), horticulture and floriculture (e.g. globe amaranth or Gomphrena globosa). The Australian amaranth Ptilotus exaltatus is likewise popular in gardens. Like many of the other species in the genus Ptilotus (commonly mulla mullas, foxtails or pussytails), P. exaltatus is at home in the arid regions of Australia.
Ptilotus contains more than 120 species, all of which are native to Australia. Ptilotus is one of the largest and most diverse genera in its family, but has been relatively under-studied despite being remarkable within the family for its diverse flowers and pollination strategies and for its interesting biogeography, genetics (e.g. relatively high chromosome number) and sexual strategies (e.g. gynodioecy, where some plants in a population have bisexual flowers and others have all female flowers). New species of Ptilotus are being discovered regularly, especially in arid Western Australia (e.g. P. actinocladus and P. yapukaratja from 2018).
A forthcoming study in the journal TAXON by Tim Hammer and colleagues from the University of Western Australia and Curtin University has produced a new evolutionary tree (or phylogeny) based on chloroplast genome sequences for Ptilotus and relatives, a group (or clade) of genera informally known as the 'aervoids'. The aervoid clade includes the Australian genera Kelita, Omegandra and Ptilotus and the African-Asian genera Aerva and Nothosaerva. Aerva javanica (kapok bush) also occurs in Australia, but is considered an invasive weed in parts of northern Australia. All individuals of A. javanica within Australia are female, as the plant spreads via seeds that develop without needing pollination. The other Australian genera of the aervoids, Omegandra, native to northern Queensland and Northern Territory, and Kelita, endemic in Queensland, were sequenced for the first time in this study.
The study revealed that the genus Aerva is polyphyletic with respect to the other genera in the clade. Kelita was found to be nested within one of the major clades of Ptilotus. The other genera were confirmed to be monophyletic.
Morphological characters were found to support the phylogeny and helped to diagnose a new generic taxonomy for the aervoids.
The polyphyly of Aerva was resolved in the study by splitting the genus into three separate genera, reinstating the genus Ouret for eight species and erecting the new genus Paraerva for two Socotran endemic species. Aerva is the now re-circumscribed in a narrow sense to include only the morphologically distinct species A. javanica.
Multiple morphological characters supported the recognition of these monophyletic clades as distinct from Aerva. Further work is required to properly delimit species boundaries within Ouret, particularly for the widespread and morphologically diverse species O. lanata (previously A. lanata).
The new phylogeny and generic taxonomy will enable future research into the evolution and biogeography of the aervoids and Ptilotus, potentially uncovering when Ptilotus arrived in Australia and what has driven its diversification in arid Australia.
Article Abstract:
Resolving intergeneric relationships in the aervoid clade and the backbone of Ptilotus (Amaranthaceae): evidence from whole plastid genomes and morphology
by Timothy A. Hammer, Xiao Zhong, Catherine Colas des Francs-Small, Paul G. Nevill, Ian D. Small, Kevin R. Thiele
I can see this being helpful for beginners and still interesting for people with more experience. Sometimes you find exactly what you need without even looking for it, and that is what happened here. There is something refreshing about content that does not try too hard and simply delivers value. I can see this being helpful for beginners and still interesting for people with more experience viking runecraft demo
I enjoyed your approach to this topic and found the explanation clear and relevant. The post is well structured, and each point builds naturally on the previous one to create a strong overall message. Please keep sharing thoughtful content like this, as it adds real value to the conversation viking runecraft apocalypse
I found this content valuable because the subject is treated with care and explained in a friendly, accessible style. I appreciate the positive tone and look forward to seeing more of your insights viking runecraft slot
Really well written and easy to follow. I picked up a few useful takeaways that I will definitely be applying going forward. This really resonated with me on a personal level, more than I expected. I was not expecting much at first but this completely won me over. You have earned yourself a new follower today temple tumble review
Your article is easy to appreciate because the writing uses clear language and makes the broader meaning of the topic easier to see. This is the kind of clear discussion that helps readers learn more, so thank you for posting it temple tumble demo