An ode to the last missing plant families

As we approach 100 million observations of vascular plants on Inat, a question popped into my head. How many plant families haven’t been observed on Inat? Surely all of them had to have been…right?
It turns out that out of 500 or so families, all but two have at least one verifiable observation on Inat. The mighty Asteraceae(asters) comprises 13%!!! of all observations, with 12.906 million observations! That’s more than double second place Fabaceae(legumes) with a “lowly” 5.822 million observations. In third place comes the Rosaceae(roses), with 4.466 million observations. Believe it or not, 26 families make up 60% of the observations!!!
Asteraceae(asters)-12.906M!!!
Fabaceae(legumes)-5.822M
Rosaceae(roses)-4.466M
Poaceae(grasses)-3.503M
Lamiaceae(mints)-2.692M
Ranunculaceae(buttercups)-2.205M
Brassicaceae(mustards)-2.125M
Orchidaceae(orchids)-1.902M
Ericaceae(heaths)-1.805M
Plantaginaceae(plantains)-1.754M
Apiaceae(carrots)-1.673M
Asparagaceae(agaves)-1.662M
Boraginaceae(borages)-1.584M
Polygonaceae(knotweeds)-1.354M
Fagaceae(oaks)-1.353M
Caryophyllaceae(pinks)-1.316M
Pinaceae(pines)-1.252M
Cyperaceae(sedges)-1.247M
Rubiaceae(madders)-1.205M
Malvaceae(mallows)-1.151M
Cactaceae(cacti)-1.140M
Apocynaceae(milkweeds)-1.125M
Euphorbiaceae(spurges)-1.044M
Caprifoliaceae(honeysuckles)-1.043M
Onagraceae(evening primroses)-1.011M
Sapindaceae(maples)-1.010M
Just left out is Solanaceae(nightshades) which barely misses the 1M mark with 975K observations.
Those 26 families making up 60% of all vascular plant observations are a true testament to the millions of awesome observers who create amazing observations. Perhaps you have seen all of these 26, or need to check a few more off your life list. However, the real question is when all the plant families will be observed.
After over an hour of scanning observations, I concluded that two vascular plant families are missing from Inat: dicot family Lophopyxidaceae, where one species of Lophopyxis is found in the Sunda Islands of Indonesia and Malaysia; and fern family Cystodiaceae, consisting of the fern Cystodium sorbifolium, native to…you guessed it, the Sunda Islands and New Guinea.
If any Inatters live on Borneo or are visiting there soon, maybe try to go out and find one(or both) of these families! Who knows, maybe they are right next to each other.

If you made it this far, thanks for reading. If you want to, please share some of the rarest or coolest plant families you’ve observed! For me it has to be Lachnanthes caroliana in Haemodoraceae, looks like an alien plant. Lachnanthes caroliana (Carolina redroot) on July 16, 2022 at 04:47 PM by Robert Levy · iNaturalist

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wow, this is such a cool analysis! thanks for putting this together & sharing!

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One of the coolest wild plants in bloom is Dudleya (Crassulaceae): https://www.inaturalist.org/observations/220970680

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Looks like I might have found Lophopyxis misidentified as Euphorbiaceae.
Compare Lophopyxis maingayi Hook.f. Source Hooker (1887), drawn from the type… | Download Scientific Diagram with Family Euphorbiaceae (spurge family) from Borneo, Lahad Datu, Sabah, MY on February 21, 2025 at 12:24 PM by Tarciso Leão. ?? · iNaturalist

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Rarest families I have observed with species I observed in parentheses

Hydroleaceae - 4,432 obs, 1/1 genus, 7/14 species (Blue Waterleaf, One-flower False Fiddleleaf)
Cyrillaceae - 5,934 obs, 2/2 genus, 4/12 species (Swamp Titi)
Schisandraceae - 6,442 obs, 3/3 genus, 48/65 species (Florida Anise)
Tetracondra - 7,043 obs, 2/2 genus, 2/3 species (Rust Weed)

Edited to add genus and species numbers: iNat/total

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Gonna be Culcitaceae(241 obs) for me. Culcita macrocarpa (Woolly Tree Fern) from Nordeste, PT-AC, PT on August 19, 2022 at 11:27 AM by Robert Levy · iNaturalist

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Great topic. I’ve seen members of three of the eleven families endemic to Australia.
Family Restionaceae (Restiads)
Family Blandfordiaceae (Christmas Bells)
And Family Dasypogonaceae which are really alien looking

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My rarest family is Ecdeiocoleaceae. Endemic to Western Australia, and only contains 3 species across 2 genera

I’ve seen all 3 of them ;)

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My rarest family is Acoraceae which has 5464 observations on iNat across 4 species in 1 genus.

In terms of looks, these plants are quite unspectacular, but they are apparently the most basal monocot family, which I think is cool.

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Another rabbit hole - picking thru Acorus obs in South Africa.

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How can you find the number of obs per family? (except by visiting each and every family, that is)

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That’s the way I did it… haha

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Lovely analysis! Love that you went on this deep data dive.

I think the rarest family of plants I can think of which I have observed is Blasiaceae (https://www.inaturalist.org/observations/239471467).
But that’s via iNat upload count. It’s least concern globally, nationally, and locally ;)

I haven’t seen it (except on FB and iNat)
Given the common name ‘guy alone’
Fynbos Endemic Family. One Genus. One sp
https://www.inaturalist.org/taxa/586193-Geissoloma-marginatum

Update: Lophopyxis maingayi from Borneo, Lahad Datu, Sabah, MY on February 21, 2025 at 12:24 PM by Tarciso Leão. ?? · iNaturalist is indeed identified as Lophopyxidaceae!!!
One more family to go!

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I love these kinds of breakdowns, very cool! Thanks for sharing!

My rarest with only one species known is https://www.inaturalist.org/taxa/64618-Welwitschiaceae with a bit over 800 observations.. well, it´s a very iconic plant even I (not a plantie usually) knew and was very excited to see and photograph even before my iNat times have started

other then that, I have 5 more families with less then 10.000 observations here
https://www.inaturalist.org/taxa/71572-Moringaceae with ~6500 observations
https://www.inaturalist.org/taxa/71489-Cyclanthaceae ~5500 observations
https://www.inaturalist.org/taxa/50920-Caulerpaceae ~9700 observations
https://www.inaturalist.org/taxa/1124031-Dicranellaceae ~2500 observations
https://www.inaturalist.org/taxa/56439-Aneuraceae ~5600 observations

Yes, many of those are from Africa or South America which I would have suspected.. but the 2500 observation family (if my ID is correct) is actually from Europe where some observers feel nothing too spectacular is possible.., who would have guessed…

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I have asked Michael Sundue to post one of his Cystodium sorbifolium observations from Borneo, which he expects to do soon.

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I went to my life list to see which families I had species in and looked at the taxa pages for family names that I don’t come across very often when learning about plants

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Yeah, I was expecting a less tedious process… (I checked my ‘life list’ too, however in my case it does not even display all families - these are notably lacking for ferns)

As far as I can tell my ‘least populous family’ at the moment is Isoetaceae (quillworts), with only 3222 obs on iNat.

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@yayemaster could probably tell you which families have the least obs, but you’d still have to cross reference that with your own obs. Unless you already know the names of all the families you’ve observed and can just pick them out of a list.

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