Large-flowered Camellia neither Gordonia nor Polyspora, probably

Back in Geoff Bogle's Arboretum again (prior to facemasks and social distancing restrictions), with Don Teese and a pretty member of the tea family (Theaceae). The tree grows adjacent to the shed where Geoff and I hung out briefly (well, for this photo mostly) after driving through the rest of the Melbourne-Gardens-sized arboretum. I'd like to say we were talking taxonomy, but were weren't (and what get discussed in the shed, stays in the shed).

So, a warning. This is taxonomy and nomenclature heavy post. There is not way around it. The plant has gorgeous flowers which smell nice. So I'll put that up front. Beyond that, though, my attention was diverted into naming the bloody thing...

Don called it Gordonia yunnanensis but said it is probably a Polyspora now, which is where all 40 or so of the Asian species once classified as Gordonia now sit. The species was first described as a Polyspora, by Hu in 1938, and moved into Gordonia by Hui Lin Li in 1944.

Well, actually not all of them. As John Grimshaw and Ross Bayton note in their New Trees: Recent Introductions into Cultivation, Polyspora can be easily confused with the genus Camellia.

Indeed, according to The Plant List, Polyspora yunnanensis of Hu is the same as Camellia taliensis, with the latter being the more appropriate name. That is, with its 'wingless' seeds (not evident the day I visited, the plant only having these immature fruits*), this species belongs in Camellia. (Although they also accept Gordonia yunnanensis, described by Hu and moved by Li,  as a accepted name.) So some uncertainty here....

Watch out too for Camellia yunnanensis, which is a different species to the one described as Gordonia yunnanensis by Hu, and was described by Combertus Pieter Cohen-Stuart in 1916.

Don Teese, Geoff Bogle and what is presumably Camellia taliensis...

Let's say we have Camellia taliensis, which seems most likely. This is the source of big- or broad-leafed tea, and our plant does have big leaves. The 'Tea Plant of Dali', I saw it described as, and the local (in Yunan) source of Pu'er (or Pu-erh) Tea.  The Flora of China seem happy with all the 'synonymy' I've outlined above, making this the current name for Gordonia yunnanensis and Polyspora yunannensis.

If I look at the Flora of China description, the young branches and trunks have 'grayish brown' bark, as you can see. To be fair, that probably applies to the majority of Camellia species.

The flowers, however, are described as up to only 5 cm across and in the diagnostic drawing provided they are proportionately much smaller (when compared to the leaves illustrated). You can see from the flower in Geoff's hand that my plant has flowers perhaps up to 15 cm across!

I sought out the couple of Camellia taliensis we have in Melbourne Gardens and found one with a couple of flowers on it. As you can see in the next picture, the flowers are far smaller than my hand, and the ones in Geoff's hand, and I can confirm that my hand is not significantly smaller than Geoff's. I can also report that the leaves seems a little thinner and perhaps more toothed on the edges.

On the other 'hand', some of the photographs of flowers and leaves posted on line for this species, such as one from Dunedin Botanic Garden, look to be a good match for the Arboretum plant. I find the most compelling match with photographs of Camellia taliensis on the New Zealand Plant Conservation Network website, where it is listed as a newly (in 2010) 'naturalised' species.

Of course, beautiful, potentially weedy and of uncertain nomenclature. Your typical garden plant!

*Thanks to Don Teese, I have now seen a photograph of the fruit and seed, sent to me on 27 November 2020. As you can see, below, the seed is clearly 'winged', and not like the seed of a typical Camellia. This would place the plant clearly within Polyspora, but now I don't know what species name to apply. Let's go with 'Polyspora yunannensis' for now, even thought the oracles say the type of this species (that is, the collection/specimen on which the name is based) is a Camellia, and therefore with wingless seeds. Apparently. Anyway, thanks Don!