T. formosana has heavily spotted, purplish pink spurred flowers which appear in early autumn, and they are up to 3 inches across. The leaves are sparingly produced. T. hirta has bell shaped flowers up to 1 inch across, with a lot more foliage - flowers may appear in late summer as well as early autumn. So basically, the flowers on T. hirta are smaller, with more leaves.

Thank you very much Bamboo. Clear and definite instructions! Going by that, my id is incorrect and I actually have hirta as none of the flowers are more than one inch across and all the plants have many leaves! THank you .

I was led to understand that T.hirta has "hairy" leaves and stems, whereas T.formasona has smooth "waxy" leaves. I'm no expert though, and as Bamboo says, T.formosana has heavier spots.
For a bell shaped flower though, you need to look to Tricyrtis ishiiana below Bamboo.

http://mailorder.crug-farm.co.uk/default.aspx?pid=9009

I don't know why the book calls hirta bell shaped - they don't look much different from formosana to me, except they're smaller...

Whoa! Now that is very different Meanie! I asked the question after going online to see if I could work it out for myself and the only difference I could see was in the spacing of the leaves, so Bamboo's answer confirmed that idea for me. Other than that they seem to look exactly the same in the photos. I suppose the heaviness of the spots is difficult to tell apart unless you have both kinds together.

So was I led to believe wrong about the hairy bit?
I was interested too, and that was the answer that I got.

Not sure about that Meanie, I haven't looked into the hairyness of the leaves question....yet! That ishiiana is stunning isn't it....very yellow!

Well the answer that I had was borne out by the fact that Sue's T.formosana is waxy. It has fewer leaves too, and the flowers are borne at the end of the stems in clusters. My three T.hirta are all hairy, and the flowers crop up at the intesections of the leaves and stems too (sometimes producing secondary stems here too) as well as at the top.
Hope Bamboo doesn't think that I'm picking a fight, as I wpild like to know the definitive answer too!

Not at all, Meanie, fear ye not. I've no idea whether they're hairy or not, never having grown them - I just checked out the Encyclopaedia for the info, and hairy isn't mentioned - or is it, maybe I missed that bit, I'll have another look...

The Ishiiana is very different. Crug farm has opened up a whole new world of Tricyrtis for me (thanks Louise).

Hmm interesting, the only mention of 'hairy' is in the description of the flowering stem on T. ochroleceum.

I have a spare packet of seeds if you'd like to give them a shot!

Um, thanks very much, but they're not really my cup of tea! I'm a shrub/foliage kind of person rather than flowers as such. Not keen on spotted flowers like that either... I don't know why but they remind me of chopped liver - not keen on orchids either... I know, I'm weird...

Why is it weird to have your own personal tastes?

I don't think it is, but you should see the reaction when I say that I don't like orchids - you'd think I'd suggested walking round tesco naked...

I get the same reaction when I say that I don't like variegated foliage!

See now I love it, variegated foliage I mean - but I have known quite a few people who just think the plant looks sick, don't like it at all. But I've never met anyone who also dislikes orchids...

lol...you two! I can understand the dislike of variegation....although I like it because it adds light colour in winter. I can also understand the dislike of orchids.....although I do like them! I'm glad we all have our different tastes....I enjoy that diversity of style, and enjoy some gardens that I wouldn't dream of emulating...like Bluespruce's evergreen oasis for example; and sometimes people get me into stuff that in the past I haven't liked. My pet hates are currently Dahlias and Chrysanthemums....but now I'm starting to waver about the dahlias because I've seen some nice ones this year! Tell you one thing I'm never going to do though....walk around Tesco naked!! :))

Ha ha, no, neither am I - for a start, at my age, I'd definitely frighten the horses, and secondly, its FREEZING in Tesco!

I prefer not to walk through Tesco full stop!
I currently dislike my orchids from the Oncidium alliance - three great spikes formed on them, and then died!!!

Sainsburys is even colder!! Meanie, did you see my comment about my orchid that I was transporting to my daughter's flat and managed to chop the flower stem off in transit!!! grrrrrrrr :((((

I try to avoid supermarkets period - it's the trotski in me I guess!
My cats good at that trick with my orchids!!

Well, the cat is clearly not a fan either then! :)