Journal archives for October 2023

October 08, 2023

Gazania in Australia

Gazania is a relatively small genus of 19 species (plus one hybrid taxon) in Asteraceae native to southern Africa. Many Australians are familiar with the genus not only because it's a popular garden plant and widely planted along median strips, in suburban parks, and in other public settings by councils, but unfortunately because it's a very widespread and often abundant weed. Naturalised in every Australian state and territory except the Northern Territory (although the AVH does contain a single collection from Alice Springs which, based on the collection notes, was clearly not planted), as well as Norfolk Island, Gazania are usually found growing as weeds in grassy wastelands, along road verges, or in back dunes and sandy areas along the coast. In some regions, including areas in southwestern Australia, they can become hugely prolific and dominate large areas.

The Australian Plant Census, and all state floras, recognise two species as naturalised in Australia: Gazania linearis and Gazania rigens.

Here is the NSW genus treatment: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Gazania
Victoria: https://vicflora.rbg.vic.gov.au/flora/taxon/2cc9dfd7-92e1-49b0-b5a7-2d96691afd3a

At time of writing, the AVH contains 385 collections of Gazania from Australia, dating all the way back to 1902. Fifteen of these are currently only determined to genus, 112 as G. rigens, and 258 as G. linearis. I have no doubt that at least a small percentage of these collections represent cultivated specimens which have not been annotated as such, but overall the collections seem to paint a clear picture of these two species being widely naturalised, especially G. linearis.

However, thanks to the knowledge of South African botanists @steven_molteno and @jeremygilmore, it seems almost certain that the name G. linearis has been misapplied in Australia, and that all collections actually represent the hybrid taxon Gazania × splendens.

Comments regarding this situation are distributed across a number of observations, but a very good summary of the most important information can be found in the conversation here: https://www.inaturalist.org/observations/63065542 [UPDATE: at some point in the past few weeks, either the user who uploaded this observation deleted it, or they deleted their account entirely. I have no idea why, but this observation is now gone forever, and unfortunately the very useful comments lost with it. I have tagged Jeremy and Steven below in the comments to try retype some of them]

Long story short: Gazania linearis is almost certainly not present in Australia, not being found in the nursery trade; the best name to apply to specimens from Australia is Gazania × splendens; G. rigens is legitimately naturalised in Australia, although it can be very difficult to ID many specimens/differentiate them from Gazania × splendens, and indeed:
"The original cultivars that naturalised were already interspecies hybrids, even before they went feral. Since going invasive they've undoubtedly just continued mixing even further...They can all [including rigens] safely, correctly and easily be swept into the x splendens basket!

There's an interesting 2009 paper titled Globally grown, but poorly known: Species limits and biogeography of Gazania Gaertn. (Asteraceae) inferred from chloroplast and nuclear DNA sequence data, which can be downloaded from this link. One of their main findings was that:
"Of the 15 species sampled, only 7 are supported as monophyletic. Most of the remaining taxa form a large, poorly resolved clade corresponding to a large, morphologically variable species complex."

Gazania linearis and Gazania rigens both fall under this complex (the 'K-R complex').

Posted on October 08, 2023 09:37 AM by thebeachcomber thebeachcomber | 18 comments | Leave a comment

October 30, 2023

Check old Ericaceae observations

Unfortunately an Australian user with thousands (tens of thousands from memory) of identifications, mostly of Ericaceae (especially on the east coast), deleted their account a few weeks ago. These IDs have all now been lost.

I won't get into a discussion here about the pros/cons of allowing all content to be deleted (there are numerous forum threads about this issue, I recommend having a read of those), but I wanted to make this post as I believe most people won't have realised this user deleted their account and thus all of their IDs (I only even realised as @jackiemiles brought it to my attention today). Unfortunately the deletion was long enough ago now (> two weeks) that staff basically cannot retrieve a backup without shutting down all of iNat, which obviously is not feasible.

So I'm tagging top IDers and observers of Ericaceae in Australia (mostly east coast) here; if you have some time over the next week or two, it would be great to go back through old records and add IDs where you can. In particular, there will be many observations of easily IDed species that were RG but have now shifted back to Needs ID (eg there are now over 100 records of Epacris longiflora that have shifted back to Needs ID where only two IDs were present, the observer and the deleted user).

Also, and perhaps most importantly, there will now be records with incorrect IDs due to the deleted IDs having been corrective.

Given I do not know why the user deleted their account, please do not name them here if you do know who I'm referring to, and don't speculate as to why they deleted their account, as I do not think this is productive.

As usual, please tag anyone else I may have missed

@alan_dandie @mftasp @george_seagull @jggbrown @reiner @elizabethhatfield @cynthia_c @bushbandit @iancastle @bean_ar @mattintas @cobaltducks @gtaseski @insiderelic @michaelcincotta @annabelc @margaretjb @gregtasney @nicklambert @possumpete @heathwallum @scottwgavins @aavankampen @lukemcooo @chrisclarke @dustaway @onetapir @rfoster @vireyajacquard @helen_y @dj_maple @adrian2370 @buffsky

Posted on October 30, 2023 05:03 AM by thebeachcomber thebeachcomber | 8 comments | Leave a comment