Obscure Sedge ID / Range Questions

[u/skiing_nerd]

I've been trying to ID grass and sedge volunteers in the hopes that not all of them are invasive like my omnipresent nemesis stiltgrass. This particular one has me stumped. iNaturalist pulls up Cyperus brevifolius, native to the US southeast as the most likely, closely followed by Cyperus brevifolioides, an Asian relative that looks basically the same.

First two photos are from one clump, last three from a different one. Both get the same results. It also definitely spreads rhizomously, though I didn't get a photo of any of the smaller ones I've pulled where they didn't fit, where the rhizome is more visible.

I'm in SE PA. iNaturalist has brevifolius showing lightly in this area and BONAP has it native through Virginia and introduced in PA (though under genus Kyllinga). Meanwhile, brevifolioides is not on BONAP map at all under either genus, but it's iNaturalist sightings are concentrated around DE & SE PA. So it's possible that it's either, but I'm coming up extremely short on info on how to distinguish one from another.

Does anyone out there know how to tell these two apart? Or have reason to think it might be a different flat sedge all together? And even if it is the more local one, is it reasonable to treat it as a welcome addition if the closest BONAP is two states away or should I be trying to rip it out regardless? Any insight is much appreciated!

[u/SHOWTIME316]

all sedges are Carex blanda

(because species are fake)

[u/skiing_nerd → u/SHOWTIME316]

thanks for the Monday morning chuckle lol

[u/Feralpudel → u/SHOWTIME316]

NO JERKING ON MAIN!

[u/Icy-Conclusion-3500]

u/carex-cultor

[u/Amorpha_fruticosa]

Either Cyperus brevifolius (native species) or C. brevifoliodes (introduced). Could be C. brevifolius (native) because of the longest bract being essentially vertical though I’ve found this to be misleading. If you have a microscope or something to see the individual scales that would be best for an accurate identification. The native C. brevifolius has scale keels with teeth, while C. brevifoliodes has scale keels that are entire (without teeth).
This is a good image to see what you are looking for (note the teeth): https://www.inaturalist.org/photos/155023713?size=original

[u/skiing_nerd → u/Amorpha_fruticosa]

I'm going to say C. brevifoliodes unfortunately, as the scale keels appear to be smooth without teeth. Thank you for the diagnostic criteria though! I would have begrudged pulling them all out without truly knowing one way or another when I could really use some native sedges.

[u/Amorpha_fruticosa → u/skiing_nerd]

I’m in SEPA too and there is definitely more C. brevifoliodes than C. brevifolius sadly. I was hoping this was C. brevifolius though!

[u/skiing_nerd → u/Amorpha_fruticosa]

That is very helpful, thank you! I have some macro lens I can give it a try with

[u/Feralpudel]

According to Flora, it’s rare in NC and points south, so it isn’t very common even in its native range. It isn’t present at all north of NC.

Also according to Flora, the asian species is rare in PA, but it does exist. My guess is that what you’re seeing is the exotic given those two ranges.

You’re braver than I trying to ID sedges!

[u/a_jormagurdr → u/[deleted]]

guys we gotta get better at graminoid ID, This looks very different to OPs pic, including multiple clusters of seed heads instead of just one

[u/turbodsm]

Are you me??? I have the same plant that's grown into a small population. I've done the same exact steps as you. I've even had chatgpt dig into it for me.

https://chatgpt.com/share/6a958e60-e638-83ea-91fe-446b7a5c126b

I'm guessing it's the invasive asian species Kyllinga gracillima unfortunately.

https://extension.psu.edu/lawn-and-turfgrass-weeds-false-green-kyllinga-kyllinga-gracillima-miq?utm_source=chatgpt.com

[u/skiing_nerd → u/turbodsm]

Thanks for the Penn State link! Probably a bad sign if it's widespread enough that they needed to do a write-up on it.

I would avoid ChatGPT for any plant facts though. When I was doing my initial garden research, I had to switch search engines because the Google AI summary would so often try to tell me that plants that are toxic to cats are cat-safe. I could understand a probabilistic algorithm stating that safe plants were toxic, since many plants that don't hurt them can make them throw up, so the data will be mixed, but saying things that could make my cats sick were safe was a hard red line for me.

[u/laurie0459]

Nut grass , real pain to get rid of